Radio communication system including SDL having transmission rate of relatively high speed

ABSTRACT

A large amount of user information is transmitted with good efficiency by means of a high-speed downlink by making transmission rates of an uplink circuit and a downlink asymmetrical. The radio communication system includes a plurality of base stations, a plurality of terminals, an uplink established between each of the base stations and each of the terminals for the purpose of radio transmission of prescribed information from a terminal to a base station, and a downlink circuit established between each of the terminals and each of the base station for the purpose of radio transmission of prescribed data from a base station to a terminal. This radio communication system has a low-speed transmitting means, provided at the terminal, which transmits a radio signal at a relatively low transmission rate to an above-noted base station via the above-noted uplink, a low-speed receiving means, provided at the base station, which receives a radio signal sent at a relatively low transmission rate from one terminal via the uplink, a high-speed transmitting means, provided at the base station, which transmits a radio signal at a relatively high transmission rate to an above-noted terminal via the above-noted downlink, and a high-speed receiving means, provided at the terminal, which receives a radio sent at a relatively high transmission rate from the base station via the downlink.

This application is a continuation, of application Ser. No. 08/492,728,filed Jun. 20, 1995 now U.S. Pat. No. 5,754,961.

BACKGROUND OF THE INVENTION

The present invention relates to a radio communication system, and morespecifically to a radio communication system for the purpose ofperforming super highspeed downlink (abbreviated SDL, this abbreviationused hereinafter), which has a relatively high transmission rate on thedownlink, which is the radio transmission path from the base station tothe terminal, in comparison with the transmission rate on the uplink,which is the radio transmission path from the terminal to the basestation.

In recent years, with advances in communications and informationprocessing technologies, a variety of types of radio communicationsystems such as a personal-use portable telephone (Personal HandyphoneSystem (PHS)) and systems which make use of the above-noted SDL havebeen proposed.

Radio communication systems such as PHS or local area networks (LANs)which use radio are experiencing increasing demand, by virtue ofadvancements in various information media, and along with this increaseddemand comes an increasing necessity to perform radio communication overa variety of networks. In view of this type of necessity, a broadeningof the transmission frequency bandwidth is desired in radiocommunication systems as it is in cable communication systems. In radiocommunication systems of the past, the uplink for sending a radio signalfrom the terminal to the base station and the downlink for sending aradio signal from the base station to the terminal had transmissionspeeds which were matched for bi-directional radio communication.However, the actual situation is that the amount of transmission on thedownlink, over which user information requested by the user is sent tothe terminal is considerably larger than the amount of transmission onthe uplink over which only control information or the like is sent.

This is a problem not only with mobile communication, but also withradio LANs and a variety of other radio services. However, because thefrequency spectrum resources for radio are limited, it is difficult towiden the frequency bands for currently implemented services, making itdesirable that higher, unused frequencies (such as sub-millimeter andmillimeter bands) be developed.

FIG. 1 shows an example of the frequency placement in the past. This isthe example of the Japanese digital system mobile telephone system RCRSTD-27B (Research Center of Radio System STanDard 27B). In this system,the downlink and the uplink have the same transmission rate, there beingsystems that operate in the 800-MHz band and the 1.5-GHz band. In eitherof these frequency bands, the uplink and the downlink are in the samefrequency band. In the 800-MHz band, the downlink is located in therange 810 MHz to 826 MHz, and the uplink is located in the range 940 MHzto 956 MHz. In previous systems, because an uplink and a downlinkoperating at the same transmission rate were assumed, transmission isperformed in the same frequency band. However, problems arise withapplication to the SDL system.

In the SDL system, because a wideband downlink is assumed, in a lowfrequency band such as the 800-MHz band, it becomes difficult to assignthis wide band and to achieve effective frequency usage. For example, inthe case of trying to perform transmission at 100 MHz or so, it isobvious that it is impossible for the bandwidth to be found to allow oneuser 100 MHz bandwidth in the 800-MHz band. For this reason, it isnecessary to perform transmission in the sub-millimeter band of severalgigahertz, or in the millimeter band of several tens of gigahertz.

The US mobile telephone system can be cited as an example of a radiocommunication system of the past which had differing transmission rates.In this system, at the point at which a switch was being made fromanalog to digital, the mobile telephone handset was made to include bothan analog and a digital mobile telephone, thereby enabling calling andreceiving of calls in both areas. In this system, two completelydifferent communication systems—analog and digital—are used, thehandsets having few circuits in common, so that there were one each ofthe analog mobile telephone and the digital mobile telephone. For thisreason, a problem existed in that the circuit was of a large scale.

Next, the previous method of synchronizing the signal source used as areference will be described, using FIG. 2. FIG. 2 shows theconfiguration of a phase-locked loop (PLL) for the purpose of obtaininga frequency that is n/m times that of the oscillation frequency of areference oscillator. A signal having the oscillation frequency x isfrequency divided to 1/m by a frequency divider 201, and input to aphase comparator. A signal from a voltagecontrolled oscillator (theoscillator frequency of which, y, is controlled by a voltage) isfrequency divided to 1/n by a frequency divider 202, and input to thephase comparator. At the phase comparator, a voltage value is outputwhich is responsive to the phase difference of these two signals. Thephase comparator output is input to a loop filter which establishes thefrequency tracking characteristics of the PLL. The loop filter output isinput to the voltage-controlled oscillator. The PLL is controlled sothat the phase difference between the two signals at the input of thephase comparator is zero. Therefore, the following equation (1) obtains.x/m=y/n  (1)

Therefore, the output y of the voltage-controlled oscillator is asfollows.y=xn/m  (2)

From the above, by means of the frequency divider 201 and the frequencydivider 202, the frequency becomes n/m times and is synchronized to thereference oscillator.

By using a PLL in this manner, it is possible to obtain a signal of n/mtimes the frequency of and synchronized to the reference signal source.However, the method of using a PLL requires a VCO (voltage-controlledoscillator), thereby requiring a separate oscillator.

While control data and user data has been transmitted on the same radiofrequency, the amount of user data was much greater than the amount ofcontrol data. In addition, user data and control data are transmittedand received separately.

It was inefficient and uneconomical to send a small amount of data overa wide transmission path. And large amounts of data require a widetransmission path.

Unless a high transmission frequency is used, it is not possible toestablish a wide transmission path, and if a small amount of data issent over a wide transmission path, it is difficult to form atransmission path, because of jitter and the like, which is caused byfrequency.

As described above, to handle the transmission of diverse and largeamounts of information such as in the PHS and LANs, if the transmissionspeeds of the uplink from the terminal to the base station and thedownlink from the base station to the terminal are the same, it was notpossible to make effective use of the radio circuit.

In a millimeter band such as the 60-GHz band, because of the highfrequency, the electromagnetic propagation loss becomes extremely high.For this reason, when performing communication over somewhat of adistance, the transmitting power must be made large. The portableterminal of the type used in the SDL system is used in the proximity ofthe human body, making it unsafe from a health standpoint to transmitwith high power from the terminal. A portable terminal usually ispowered by a battery, and transmission with a high power leads to theproblem of a shortening of the period of use before recharging orreplacement of the battery.

In addition, millimeter-band devices are extremely expensive, and therequirement to use millimeter-band transmitting devices in a terminalmakes it difficult to meet requirements for reduction in price. From thestandpoint of volume as well, the use of millimeter-band transmittingdevices makes it difficult to reduce size.

The ideal method of modulation will differ, depending upon what items ofthe transmitting bandwidth (transmission rate), the frequency band, thesize of the transmitting/receiving circuit, the devices selected, andfrequency utilization efficiency is to be given priority. For example,in narrow band communication such as in a mobile telephone, if frequencyutilization efficiency is to be given priority, π/4DQPSK or QAM is used.However, in the case of wideband radio communication, these types oflinear modulation require radio components that operate linearly over awide bandwidth, making reduction of size and reduction of powerconsumption difficult.

In the SDL system, in which the uplink and downlink clearly havedifferent transmission rates, if the same modulation method or methodswhich are similar in characteristics are used, there is no choice but toeither adjust to one of the modulation methods or to use a compromisemethod for both the uplink and the downlink, even if performance drops.

In addition, in radio communication systems of the past, thetransmission of a variety of quality information was made possible byproviding radio communication systems having different transmissionmethods. That is, by housing two transceivers for different transmissionmethods in the same case, it is possible to implement diversifiedtransmission quality. For this reason, there was the problem of theincrease in size of the constitution of the transceiver.

SUMMARY OF THE INVENTION

The present invention has an object to provide a radio communicationsystem which, by making the downlink transmission rate relatively fastin comparison with the uplink, enables the high-speed transmission ofinformation to the terminal via the downlink, and which further has highfrequency utilization efficiency.

Another object of the present invention is to provide radiocommunication system capable of an increase in the frequency bandwidthused to a bandwidth equivalent to that used in cable communicationsystems.

Yet another object of the present invention is to provide a radiocommunication system having a signal transmission rate referenceoscillator with a simplified configuration, and which enables asimplification of a portable telephone apparatus for use in multimediaservice.

To achieve the above-noted objects, a radio communication systemaccording to the present invention has the following essentialconstitutional features.

A radio communication system according to the present invention is aradio communication system which includes a plurality of base stations,a plurality of terminals, an uplink circuit established between each ofthe base stations and each of the terminals for the purpose of radiotransmission of prescribed information from a terminal to a basestation, and a downlink circuit established between each of theterminals and each of the base station for the purpose of radiotransmission of prescribed data from a base station to a terminal, thisradio communication system comprising a low-speed transmitting means,provided at an above-noted terminal, which transmits a radio signal at arelatively low transmission rate to an above-noted base station via theabove-noted uplink circuit, a low-speed receiving means, provided at anabove-noted base station, which receives a radio signal sent at arelatively low transmission rate from an above-noted terminal via theabove-noted uplink circuit, a high-speed transmitting means, provided atan above-noted base station, which transmits a radio signal at arelatively high transmission rate to an above-noted terminal via theabove-noted downlink circuit, and a high-speed receiving means, providedat an above-noted terminal, which receives a radio sent at a relativelyhigh transmission rate from an above-noted base station via theabove-noted downlink circuit.

A radio communication system according to the present invention has atleast one each of the above-noted uplink circuit and downlink circuit,each of these circuits having at least two types of radio signaltransmission rates, there being at least one pair of such the circuitsin which the transmission rate of one circuit is an integral multiple ofthe transition rate of the other.

A radio communication system according to the present invention is aradio communication system which includes a plurality of base stations,a plurality of terminals, an uplink circuit established between each ofthe base stations and each of the terminals for the purpose of radiotransmission of prescribed information from a terminal to a basestation, and a downlink circuit established between each of theterminals and each of the base station for the purpose of radiotransmission of prescribed data from a base station to a terminal, thisradio communication system comprising a low-speed transmitting means,provided at an above-noted terminal, which transmits a radio signalhaving a radio frequency in a relatively low frequency band at arelatively low transmission rate to an above-noted base station via theabove-noted uplink, a low-speed receiving means, provided at anabove-noted base station, which receives a radio signal of a relativelylow frequency sent at a low transmission rate from an above-notedterminal via the above-noted uplink circuit, a high-speed transmittingmeans, provided at an above-noted base station, which transmits a radiosignal having a radio frequency in a relatively high frequency band at arelatively high transmission rate to an above-noted terminal via theabove-noted downlink circuit, and a high-speed receiving means, providedat an above-noted terminal, which receives a radio signal of arelatively high frequency sent at a high transmission rate from anabove-noted base station via the above-noted downlink circuit.

In addition, in a radio communication system according to the presentinvention the above-noted high-speed transmitting means transmits alarge amount of user information from an above-noted base station to anabove-noted terminal via the above-noted downlink circuit by means of ahigh-frequency-band radio signal, and the above-noted low-speedtransmitting means transmits a small amount of control information froman above-noted terminal to an above-noted base station via theabove-noted uplink circuit by means of a low-frequency-band radiosignal.

In addition, the present invention has an optimum connection stationinterpreting means which receives a signal for the purpose ofidentifying the above-noted wideband radio base station, notification ofwhich is made from the above-noted wideband radio base station via aradio circuit, and which interprets from this signal the wideband radiobase station that is suitable for connection, an optimum base stationnotification means which gives notification to the above-noted server ofan above-noted specific wideband radio base station that is suitable forconnection to an above-noted mobile radio station, via the above-notednarrowband radio base station, and a service starting means which startsthe above-noted prescribed service via the above-noted specific widebandradio base station which is judged to be suitable for connection withrespect to the above-noted mobile radio station.

In the case in which handover must be performed, in addition to theabove-noted means, a radio communication system according to the presentinvention has a means which, when the above-noted mobile radio stationreceives the above-noted service via an above-noted specific widebandradio base station, receives a signal for the purpose of identifying theabove-noted wideband radio base station, notification of which is givenvia a radio circuit from a wideband radio base station which isdifferent from the above-noted specific wideband radio station, andwhich interprets from this received signal to which wideband radio basestation should switching be made, a means by which the above-notedmobile radio station notifies the above-noted server via the above-notednarrowband radio base station of a wideband radio base station which issuitable as a switching destination, and a means by which theabove-noted server switches a connection with respect to the above-notedmobile radio station, that connection is made via the above-notedspecified wideband radio base station, which is judged to be suitable asa switching destination for connection, thereby providing theabove-noted prescribed service.

By virtue of adopting the above-noted constitution, the presentinvention is proposed based on the above-described goal, in which it wasstated that it makes sense for the transmission capacity of the uplinkcircuit of a terminal to be smaller than the transmission capacity ofthe downlink circuit of the base station. Specifically, because thetransmission rate at which the terminal transmits information to theuser is much higher than the transmission rate at which information istransmitted from the terminal to the base station, in view of thissignificant difference in transmission capacities, these respectivetransmitting/receiving means are constituted so as to provideappropriate transmission capacities for the uplink circuit and thedownlink circuit. It is sensible to have the transmission capacity of apersonal-use portable telephone be smaller than the receiving capacity.In addition, the user of a personal-use portable telephone receives theoutput thereof, and sends the response thereto to the personal-useportable telephone. Therefore, it is sufficient for a personal-useportable telephone to be capable of transmitting information to a basestation at a transmission rate which is lower than the transmission ratewhen information is being transmitted to the user of the personal-useportable telephone.

That is, a personal-use portable telephone receives information from abase station at a higher transmission rate that is higher than wheninformation is transmitted to the user of the personal-use portabletelephone, making it reasonable that the personal-use portable telephonetransmit information at a rate that is lower than the receiving rate.

This is highly desirable as well because of the limited battery capacityin a personal-use portable telephone. That is, the transmitting power ofa personal-use portable telephone is limited by the battery capacity,and the transmission bandwidth is severely limited by this transmittingpower. Specifically, it is desirable that a personal-use portabletelephone not perform wideband transmission, because of this limitedbattery capacity.

As described above in detail, in a radio communication system accordingto the present invention, because the uplink circuit radio signaltransmission rate is made relatively low, and the downlink circuit radiosignal transmission rate is made relatively high, it is possible to senda large amount of user information from the base station to the terminalat high speed, thereby sufficiently meeting user requirements, whilemaking effective use of the frequency spectrum.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing which shows the configuration of a PLL in the past.

FIG. 2 is a drawing which shows the frequency placement in a radiocommunication system in the past.

FIG. 3 is a block diagram which shows the basic principle of the presentinvention.

FIG. 4 is a block diagram which shows a radio communication systemaccording to the first embodiment of the present invention.

FIG. 5 is a block diagram which shows a radio communication systemaccording to the second embodiment of the present invention.

FIG. 6 is a drawing which illustrates a radio communication systemaccording to the third embodiment of the present invention.

FIG. 7 is a block diagram which shows a radio communication systemaccording to the fourth embodiment of the present invention.

FIG. 8 is a drawing which shows an example of the usual form ofcommunication.

FIG. 9 is a drawing which shows an example of a different form ofcommunication.

FIG. 10 is a block diagram which shows an example of the basicconfiguration of a radio communication system according to the presentinvention.

FIG. 11 is a block diagram which shows the configuration of the eleventhembodiment of the present invention.

FIG. 12 is a drawing which shows the utilization condition of memoryspace in the embodiment of FIG. 11.

FIG. 13 is a block diagram which shows an example of an SDL system towhich the present invention is not applied.

FIG. 14 is a drawing which shows the frequency placement of a radiocommunication system.

FIG. 15 is a conceptual drawing which shows a radio communication systemaccording to the thirteenth embodiment of the present invention.

FIG. 16 is a drawing which shows the frequency placement in thethirteenth embodiment of the present invention.

FIG. 17 is a conceptual drawing which shows a radio communication systemaccording to the fourteenth embodiment of the present invention.

FIG. 18 is a drawing which shows the frequency placement in thefourteenth embodiment of the present invention.

FIG. 19 is a conceptual drawing which shows a radio communication systemaccording to the fifteenth embodiment of the present invention.

FIG. 20 is a drawing which shows the frequency placement in thefifteenth embodiment of the present invention.

FIG. 21 is a conceptual drawing which shows a radio communication systemaccording to the sixteenth embodiment of the present invention.

FIG. 22 is a drawing which shows the frequency placement in thesixteenth embodiment of the present invention.

FIG. 23 is a block diagram which shows a radio apparatus according tothe seventeenth embodiment of the present invention.

FIG. 24 is a block diagram which shows a radio apparatus according tothe eighteenth embodiment of the present invention.

FIG. 25 is a block diagram which shows a base station radio apparatusaccording to the nineteenth embodiment of the present invention.

FIG. 26 is a block diagram which shows a base station radio apparatusaccording to the twentieth embodiment of the present invention.

FIG. 27 is a block diagram which shows a radio communication systemaccording to the twenty-first embodiment of the present invention.

FIG. 28 is a block diagram which shows a radio communication systemaccording to the twenty-second embodiment of the present invention.

FIG. 29 is a block diagram which shows a radio communication systemaccording to the twenty-third embodiment of the present invention.

FIG. 30 is a block diagram which shows a radio communication systemaccording to the twenty-fourth embodiment of the present invention.

FIG. 31 is a block diagram which shows a radio communication systemaccording to the twenty-fourth embodiment of the present invention.

FIG. 32 is a drawing which shows the service area of a radiocommunication system related to the twenty-fifth embodiment of thepresent invention.

FIG. 33 is a drawing which shows the action of a portable electronicapparatus which is used in a radio communication system related to thetwenty-fifth embodiment of the present invention.

FIG. 34 is a drawing which shows the configuration of a frequencydivider related to the twenty-fifth embodiment of the present invention.

FIG. 35 is drawing which shows the configuration of a portableelectronic apparatus used in a radio communication system related to thetwenty-sixth embodiment of the present invention.

FIG. 36 is a drawing which shows the service area of a radiocommunication system related to the twenty-sixth embodiment of thepresent invention.

FIG. 37 is a drawing which shows the configuration of a receiver for thepurpose of forming a timing generation circuit.

FIG. 38 is a drawing which shows the configuration of a receiver for thepurpose of forming a timing clock generating circuit related to thetwenty-sixth embodiment of the present invention.

FIG. 39 is a drawing which shows the input and output signals of thecarrier generating circuit and timing circuit related to thetwenty-seventh embodiment of the present invention.

FIG. 40 is a drawing which shows the input and output signals of thereference signal generating circuit related to the twenty-seventhembodiment of the present invention.

FIG. 41 is a drawing which shows the configuration of a frame timingclock generating circuit.

FIG. 42 is a block diagram which shows the configuration of the frametiming clock generating circuit related to the twenty-eighth embodimentof the present invention.

FIG. 43 is a drawing which shows the configuration of a clock generatingcircuit.

FIG. 44 is a drawing which shows the configuration of a clocksynchronization system.

FIG. 45 is a drawing which shows the system configuration related to thethirtieth embodiment of the present invention.

FIG. 46 is a drawing which shows the configuration of a clocksynchronization system related to the thirtieth embodiment of thepresent invention.

FIG. 47 is a block diagram which shows the overall concept of a radiocommunication system related to the thirty-first through thirty-ninthembodiments of the present invention.

FIG. 48 is a drawing which shows the overall configuration of a radiocommunication system related to the thirty-first through thirty-ninthembodiments of the present invention.

FIG. 49 is drawing which shows the overall configuration of a differentradio communication system related to the thirty-first throughthirty-ninth embodiments of the present invention.

FIGS. 50A-50E are drawings which show the movement of a mobile radiostations in radio communication system related to the thirty-firstthrough the thirty-sixth embodiments of the present invention.

FIG. 51 is a flowchart which shows the processing steps in a radiocommunication system related to the thirty-first embodiment of thepresent invention.

FIG. 52 is a flowchart which shows the processing steps of startingservice in a radio communication system related to the thirty-firstembodiment of the present invention.

FIG. 53 is a sequence diagram which shows communications startingprotocol in a radio communication system related to the thirty-firstembodiment of the present invention.

FIG. 54 is a flowchart which shows the processing steps in a radiocommunication system related to the thirty-second embodiment of thepresent invention.

FIG. 55 is a flowchart which shows the processing steps of startingservice in a radio communication system related to the thirty-secondembodiment of the present invention.

FIG. 56 is a sequence diagram which shows communication startingprotocol in a radio communication system related to the thirty-secondembodiment of the present invention.

FIG. 57 is a flowchart which shows the processing steps in a radiocommunication system related to the thirty-third embodiment of thepresent invention.

FIG. 58 is a sequence diagram which shows communication startingprotocol in a radio communication system related to the thirty-thirdembodiment of the present invention.

FIG. 59 is a flowchart which shows the processing steps of startingservice in a radio communication system related to the thirty-thirdembodiment of the present invention.

FIG. 60 is a sequence diagram which shows communication startingprotocol in a radio communication system related to the thirty-fourthembodiment of the present invention.

FIG. 61 is a flowchart which shows the processing steps in a radiocommunication system related to the thirty-fifth embodiment of thepresent invention.

FIG. 62 is a sequence diagram which shows communication startingprotocol in a radio communication system related to the thirty-fifthembodiment of the present invention.

FIG. 63 is a flowchart which shows the processing steps in a radiocommunication system related to the thirty-sixth embodiment of thepresent invention.

FIG. 64 is a sequence diagram which shows communication startingprotocol in a radio communication system related to the thirty-sixthembodiment of the present invention.

FIG. 65A and FIG. 65B are plan views of the mobile radio stations usedin radio communication systems related to the thirty-seventh embodimentof the present invention. FIG. 66 is a plan view of a mobile radiostation used in a system related to the thirty-eighth embodiment of thepresent invention.

FIG. 67A and FIG. 67B are plan views of mobile radio stations used in aradio communication system related to the thirty-ninth embodiment of thepresent invention.

FIG. 68 is a drawing which shows the configuration of a radiocommunication system related to fortieth embodiment of the presentinvention.

FIG. 69 is a drawing which shows the configuration of a radiocommunication system related to the forty-first embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A number of preferred embodiments of a radio communication systemaccording to the present invention will be described in detail below,with reference being made to the accompanying drawings.

Before the description of the preferred embodiments, the basic principleof the present invention will be described, using the block diagram ofFIG. 3.

A radio communication system related to the present invention has aplurality of base stations which are assigned their respective parts ofa prescribed service area, a plurality of terminals which can movearound within the above-noted prescribed service area and, as shown inFIG. 3, it further has an uplink circuit 4 which is provided betweenindividual terminals 1 and individual base stations 5 for the purpose ofperforming radio transmission of information from a terminal 1 to a basestation 5, and a downlink circuit 8 which is provided between individualterminals 1 and individual base stations 5 for the purpose of performingradio transmission of information from a base station 5 to a terminal 1.

The above-noted terminal 1 has a low-speed transmitting means 2 whichtransmits a radio signal to the above-noted base station 5 at arelatively low transmission rate via the above-noted uplink circuit 4,and a high-speed receiving means 3 which receives a radio signal sent ata relatively high transmission rate via the above-noted uplink circuit 8from the base station 5.

The above-noted base station 5 has a low-speed transmitting means 6which receives a radio signal at a relatively low transmission rate fromthe above-noted terminal 1 via the above-noted downlink circuit 1, ahigh-speed receiving means 7 which transmits a radio signal at arelatively high transmission rate to the above-noted terminal 1 via theabove-noted downlink 8. Furthermore, the reference numeral 9 denotes aterminal-side transceiving section, which includes a low-speedtransmitting means 2 and a high-speed receiving means 3.

Next the individual embodiments of the present invention will bedescribed in sequence. First, in the first embodiment in communicationwith a personal-use portable telephone held by an individual, thecommunication system used is one in which a wideband signal istransmitted from a (relay) base station to an electronic apparatus via adownlink, and a narrowband signal is transmitted from the electronicapparatus, to the relay base station via an uplink. A wideband downlinkis used for communication which includes images, voice, file editing,information distribution, advertising, broadcasting, and the like, inwhich case the uplink is used for information to control the downlink,channel selection, and, in the case of multimedia, media selectioncontrol signals, voice, and the like. FIG. 4 shows the first embodiment.

In FIG. 4, the personal-use portable telephone 1 performs transmissionand receiving with the base station 5 via the circuits 4 and 8, thishaving a transceiving section 9, a signal processing section 10 whichprocesses data received by and to be transmitted by the transceivingsection 9, an input section 13 which inputs a transmitting controlsignal, and an output section which outputs data which has beentransferred in. The signal processing section 10 is formed by aprocessor 11 which performs, among other things, A-D conversion andcoding of signals to be transmitted and D-A conversion and decoding ofreceived data, and a memory 12 which temporarily stores data which is tobe processed. The input section 13 has a keyboard 14 with numeric keysand the like for the purpose of inputting control information, and amicrophone for inputting a voice, while the output section 16 has aspeaker which outputs the voice which is related to the transferred indata, and a display 18 which displays character information and thelike.

A radio communication system related to the second embodiment of thepresent invention is applied to the case of multiple-recipientcommunications, which is a blending of broadcasting and communications.In this case, even an electronic apparatus held by an individual iscapable of receiving a broadcast signal. In such cases, one broadcastsignal selected from a plurality of broadcast signals is sent to theelectronic apparatus 1 by the relay base station 5 in response to arequest from the user of the electronic apparatus. In the future, theelectronic apparatus 1 will be usable to freely process and use theinformation taken from a broadcast. When doing this, it is possible tostore this information in the relay base station in response to arequest from the electronic apparatus, and to process it, as will bedescribed later. FIG. 5 shows one of the second embodiments.

The relay base station 5 in the above-noted type of radio communicationsystem, as shown in FIG. 5, has a transceiving section 20 which performstransmission and receiving of data with the electronic apparatus 1 viathe circuits 4 and 8, a signal processing section 25 which performssignal processing for the purpose of processing and using the data whichis received from a broadcast or the like, and a cable network terminatorapparatus 28 which accepts an information signal which is transferred invia cable network such as CATV, subscriber optical fiber cable, ATM, orthe like. The transceiving section 20 includes a sharer 21 which acceptsa control signal which is sent in from the electronic apparatus 1 andwhich outputs data to be sent to the electronic apparatus 1 via anantenna, a receiving section (Rx) 22 which converts a received radiofrequency (RF) signal to a prescribed-frequency signal, and atransmitting section (Tx) 23 which converts data to be sent to an RFsignal. The signal processing section 25 has a processor 26 whichselects a channel from channels of data, in response to user requestsfrom various electronic apparatuses 1 which are input via the cablenetwork terminator apparatus 28, and which performs signal processingfor the purpose of sending the selected desired data to an electronicapparatus 1, and a memory 27 which stores the desired data in responseto the above-noted request of a user.

In the second embodiment, the electronic apparatus need not be forpersonal use. That is, it can be used by a number of persons, such asthe case in which it is for family use. In particular as shown in FIG.6, the relay base station 5 is mounted to electrical utility poles orthe like, with optical cable or coaxial cable, or the like use totransfer information to that point. It is also possible for anelectronic apparatus 1 which is mounted at home or in a vehicle to havea base station of a cordless telephone used at home, a VCR, or ahome-use workstation or the like connected to it. In such a case, theelectronic apparatus 1 transmits to the relay base station 5 informationand information as to whether or not the information requested is to bestored, in accordance with a request from such home equipment. Inaccordance with this, the relay base station 5 selects information, andin some cases transfers it to the electronic apparatus 1 as it storesit.

The third embodiment is applied in the case in which the apparent amountof information generated by a human is large, the received informationbeing processed and further retransmitted.

That is, there are cases in which a file A is received, this isprocessed or added to convert to the form α(A)+β and then retransmitted.In this case, α(A)+β appears to be a large amount of information.However, there are the operation of conversion to the amount ofinformation α(X) that a human generates and the added information β. Theamount of information required to express the conversion operation α(X)and the added information β are information that a human generates, thespeed of generation thereof not exceeding the speed at which the humanbrain and body can generate information. That is, it does a given speed.Specifically, it is low in comparison with the speed at which speed atwhich a human can receive information. In such cases, instead oftransmitting α(A)+β, it is acceptable to transmit only the conversionoperation α(X) and β, these being used at the base station to generateα(A)+β, the result sent to the far end party.

Operations such as file editing can all be implemented with these typesof operations. That is, the original file is transmitted to the portableterminal via a wideband downlink, which is then looked at and edited bythe user. The screens that are looked at and edited by the user areupdated in accordance with the editing performed. Along with this, theediting information is sent to the base station, where the original fileis edited based on this editing information. By doing this, editing ispossible with an extremely small amount of transmission from theportable terminal to the base station.

By means of the above-noted operations, it is possible to reduce theradio transmission bandwidth, to reduce the radio transmitting power,and to perform efficient information transmission with a rechargeablebattery.

This type of processing can be applied to examples other than the fileoperation noted above. Specifically, assume that A is the data for theface and the voice of a user of a personal-use portable telephone, andthat these are stored at a base station or relay station. Thepersonal-use portable telephone then transmits to the base station onlythe content of the speech and parameters for intonation different fromthe usual. Or else only expressions that are differ greatly from theuser's normal facial expression or other emotional expression parametersare sent by radio. At the base station, these are synthesized toresynthesize the original voice or the original screen transmission. Bydoing this, it is possible to reduce the radio transmitting power, andto perform efficient information transmission with a rechargeablebattery.

In addition, a relay base station which performs such processing asα(A)+β can be in the same position as the radio transceiving apparatus,but can also be at a remote location which is connected to acommunication network inside, for example, the electronic apparatus'suser computer or inside equipment at the far-end party.

The third embodiment is shown in FIG. 7. The relay base station 5,information amount expanding server 30, communication far-end server 31,information generating source database 32, and the like are connected,for example, in a network such as a LAN, MAN, or ATM network. Theinformation generating source database 32 transmits information A to theelectronic apparatus 1 via the relay base station 5. Along with this,the information A generates the processing operator α(X) and addedinformation β. The electronic apparatus 1 transmits these processingoperator α(X) and added information β to the information amountexpanding server 30, via the relay base station 5. The amount ofinformation this operator and added information have is the amount ofinformation that is generated by the human who is the user of theelectronic apparatus 1, this capacity being small. At the informationamount expanding server 30, information A is processed by the processingoperator α(a) and the added information β, α(A)+β is generated, thisbeing sent to the server 31. The information amount expanding server 30send the processed information α(A)+β to the electronic apparatus 1A viathe relay base station 5A, and this can be displayed on the display 18of the electronic apparatus 1A, or α(A)+β can be made at the electronicapparatus 1 and displayed on the display 18.

There are cases in which the apparent amount of information generated bya human is large. This is the case in which the received data isprocessed and then retransmitted. That is, it is the case in which theoriginal information A is received at a portable electronic apparatus,this being processed or added to, converting it to the form α(A)+(B),and retransmitting it. In this case, the α(A)+β can appear to be data ofgreat quantity. There are many cases in which there is a large amount ofthe original data A. However, there are the operation of conversion tothe amount of information α(X) that a human generates and the addedinformation β. The amount of information required to express theconversion operation (X) and, the added information β are informationthat a human generates, the speed of generation thereof not exceedingthe speed at which the human brain and body can generate information.That is, it does not exceed a certain speed. Specifically, it is low incomparison with the speed at which speed at which a human can receiveinformation. In such cases, instead of transmitting α(A)+β, only theconversion operation α(X) and β are transmitted, these being used at thereceiving side to generate α(A)+β, the result being the same.

That is, the relay base station sends A to the electronic apparatus, andalong with that A is stored at the relay base station. Then, theelectronic apparatus looks at A, while transmitting only the informationα(X) and the conversion operator β to the relay base station.Simultaneously with this, at the electronic apparatus α(A)+β is made anddisplayed, while the relay base station also makes α(A)+β and sends thisto the far end. By means of the above, it is possible to implementservice which requires the transmission of large amounts of data,without using excessive frequency resources and by means of low-capacitybattery power.

Furthermore, a communication system such as described above, in whichwideband signal transmission is performed via a downlink from a relaybase station or base station to an electronic apparatus or apersonal-use portable electronic apparatus and in which narrowbandsignal transmission is performed via an uplink from an electronicapparatus to a relay base station is implemented in the fourthembodiment, which is shown in FIG. 4.

In the fourth and fifth embodiments, there are two modes ofcommunication with an electronic apparatus held by an individual, one inwhich wideband signal transmission is performed via a downlink from arelay base station to the electronic apparatus, and in which narrowbandsignal transmission is performed via an uplink from the electronicapparatus to the base station, and another in which narrowband signaltransmission is performed in both directions. A wideband downlink isused for communication which includes images, voice, file editing,information distribution, advertising, broadcasting, and the like, inwhich case the uplink is used for control signals or the above-notedconversion operators. The communication mode in which narrowband signaltransmission done in both directions is used when both sides aretransmitting voice or low-speed data. That is, it is very desirable thatthere be one narrowband uplink and two downlinks, one narrowband and onewideband. The fifth embodiment is shown in FIG. 9. In FIG. 9, thereference numeral 34 is the narrowband downlink circuit used for lowfrequencies. In addition, it is desirable that which of these two is tobe used is established by a request from an electronic apparatus. Thatis, when there is a call from an electronic apparatus, if it is a voicesignal the narrowband downlink is requested, but if it is an imagetransmission request, the wideband downlink is requested.

FIG. 10 shows a radio communication system related to this fifthembodiment. The configuration shown in FIG. 5 differs from theconfiguration shown in FIG. 3 in the low-speed transmitting means 35provided at the base station 5, the low-speed receiving means 36provided at the terminal 1, and the above-noted downlink circuit 34between this low-speed transmitting means 35 and low-speed receivingmeans 36.

In the case in which communication is started from the electronicapparatus, first it is reasonable that the narrowband link of FIG. 10 isused to transmit to the base station or relay base station what kind ofcommunication it is, a selection of one of the two downlinks being madebased on the transmitted signal, the links in both direction being thenopened. When a transmission intended for the electronic apparatusreaches the relay base station, in the case in which both a narrowbandand a wideband downlink are provided, first the narrowband downlink isused to inform the electronic apparatus that a call for it has beenreceived, whereupon the electronic apparatus informs the base stationwhether or not it can use that link to the call to receive it, and acorresponding link is assigned.

In this case, the narrowband link itself can also be a narrowbandbi-directional transmission means which operates independently. Forexample, it is possible to use the TDMA/TDD (time division multipleaccess/time division duplex) form of transmission.

The sixth embodiment is applied to the case in which frequency placementproblems exist when the bandwidths of the uplink and the downlink differgreatly. Specifically, in the case in which this is to be implementedusing FDMA/FDD (frequency division multiple access/frequency divisionduplex), if the specifications of the sharers of the terminals are allmade the same, it is desirable that the frequency spacing of the uplinkfrequency and the downlink frequency be the same. When this is done, onthe narrowband uplink, the frequency difference between adjacentchannels becomes much greater than the uplink bandwidth, leaving much ofthe frequency band unused, quite an undesirable condition. Therefore, apseudorandom signal series is used to achieve bandwidth dispersion onthe uplink, so that transmission is done with almost the same bandwidthas the downlink. If the dispersion ratio is large, the uplink frequencycan be made the same as other systems.

The seventh and eight embodiments are applications to the case in whichlong-distant transmission is not possible because of the tendency of thehigh-speed downlink to be influenced by multipath. There is also adesire to perform long-distance transmission, even if the bandwidth isnarrow. In such cases, a signal to be transmitted a long distance isdispersed using a pseudorandom series having a long period and thentransmitted, and a short-distant large capacity signal is dispersedusing a pseudorandom series having a short period and then transmitted,thereby enabling satisfaction of both requirements. In addition, becauseit is possible to select the transmission rate freely by selecting theseries, in response to the position at which the electronic apparatusexists, it is possible to perform communication with high flexibility inthe case in which there is a mixture of signals with various bandwidths.It is also possible, in the case in which there are radio circuits withdiffering original data rates, to use pseudorandom series of theappropriate length so each of the circuits has approximately the samebandwidth after dispersion, thereby enabling the provision of a radiocommunication system which is flexible and which enables effective useof frequency bandwidth.

In addition, in the case in which this kind of bandwidth dispersion isused, because it is possible to use the same frequency band for aplurality of links, it is easy to achieve a reduction to a small sizeand weight, for facilities in the base station or relay base station,and also for the personal-use portable electronic apparatus orelectronic apparatus.

The ninth embodiment is applied in the case in which the timing oftransceiving is different between transmitting and receiving, these notbeing performed simultaneously, thereby enabling free selection of theuplink and downlink frequency, enabling even more effective use offrequencies.

The tenth embodiment is applied to accommodate the case in which toaccommodate a radio LAN or the like, if the uplink is randomly accessed,access to a server or database connected to the network can be performedby a simple protocol.

The eleventh and twelfth embodiments will be described using FIG. 11through FIG. 13.

FIG. 11 is a block diagram of the eleventh embodiment, which shows theconfiguration of an SDL system to which the present invention has beenapplied. As illustrated therein, a memory 42 is provided between aninformation providing station 41 and a base station 5, information whichis obtained via a communication circuit 43 being stored in the memory.The portable electronic apparatus 1 accesses the base station by radiocommunication, almost all the information that many electronicapparatuses desired being stored in the memory, enabling the passage ofmuch information to be executed merely via the connecting line 44.

While this functions for a radio communication post and memory as well,a different embodiment of the present invention enables connectionsbetween one memory and a plurality of radio communication posts.

FIG. 12 is a drawing for the purpose of describing the condition ofmemory in the system of the eleventh embodiment of the presentinvention. The information 47 and 48, which is obtained from theinformation providing station, is placed in the memory. The frequency ofaccess of this information is differentiated into levels, and when thereis a new information access, the stored contents are discarded, startingfrom information 23, which has a low access frequency, with newinformation 46 being written into memory area 45.

As another embodiment, in the case in which the memory area issufficiently large with respect to the amount of information, it ispossible to write all of the information into memory beforehand.

As yet another embodiment, in the case in which there is an effectiveperiod of time for the information, such as in the case of a newspaperor a magazine, it is possible when the time limit has come, to erase theinformation from the memory, or to overwrite it with new information.

FIG. 13 is a drawing which shows the information providing serviceaccording to an SDL system related to the twelfth embodiment. Theinformation providing station 32 provide information such as newspapers,magazines, images, avoice, traffic, or personal information. Theinformation providing station is connected to the base station 5 bymeans of a communication circuit 49. The base station is installed at atransport station, a structure, or on a road, and sends information inresponse to a request from a portable electronic apparatus 1, orinformation is sent continuously from the base station.

A radio communication system in accordance with the above-describedfirst through twelfth embodiments, is related to the SDL system, theprinciple of which is shown in FIG. 4. The radio circuit is formed by awideband downlink from the base station to a personal-use portableelectronic apparatus, and a narrowband uplink from a terminal to a basestation. In these embodiments, on the case in which the transmissionrates of the uplink and the downlink are asymmetrical is proposed,nothing being said about frequency placement or method of modulation.

A frequency placement example of the past is shown in FIG. 1. This isthe Japanese RCR STD-27B digital automobile telephone system. In thissystem, the downlink and the uplink have the same transmission rate, the800-MHz and 1.5-GHz bands being used as the radio frequency bands. Inthe 800-MHz band, the downlink is located in the range 810 MHz to 826MHz, and the uplink is located in the range 940 MHz to 956 MHz. In asystem of the past, because an uplink and a downlink operating at thesame transmission rate were assumed, transmission is performed in thesame frequency band. However, problems arise when consideringapplication to the SDL system.

In the SDL system, because a wideband downlink is assumed, in a lowfrequency band such as the 800-MHz band, it becomes difficult to assignthis wide band and to achieve effective frequency usage. For example, inthe case of trying to perform transmission at 100 MHz or so, it isobvious that it is impossible for the bandwidth to be found to allow oneuser 100 MHz bandwidth in the 800-MHz band. For this reason, it isnecessary to perform transmission in the sub-millimeter band of severalgigahertz, or in the millimeter band of several tens of gigahertz.

An example of the frequency placement in the case in which a radiocommunication system related to the present invention is configuredusing a 60-GHz-band SDL system is shown in FIG. 14.

The amount of information that a human being is capable of generatinghas an upper limit due to the capability of a human being. In contrast,the amount of information that a human can perceive is much greater thanthe amount of information that a human can generate. The informationthat a human can generate is limited, even if we add together voice,input from a keyboard or a mouse, facial expressions, and all otherinformation. The amount of information in the human voice falls farshort of 64 kbps. Even if various means of transferring data between thehuman and a machine, such as a keyboard or a mouse, are used, none ofthese can surpass the amount of information that can be generated by thehuman mind or parts of the body, and in total the amount of informationthat a human being can generate is thought of as not exceeding 100 kbps.

In contrast to this, the amount of information that a human being canreceive is extremely large. The human being receives a plurality ofsensory media, such as voice, images, atmosphere, tactile senses, andsmells, and the like, using perception organs that operateindependently. In addition, the brain and the organs of a human beingprocess the information they receive, extracting and processing onlyinformation which can be processed by the brain and the bodily organs,in response to the individual human's history and processing priority.In normal everyday life, much more information than can be generated bya human being is received. And feedback is applied to an informationreceiving means which selects which information is to be accepted, basedon the received information. The manner in which this feedback isapplied differs from individual to individual. Therefore, even if alarge number of humans receive the same information, the method ofprocessing it will differ greatly. That is, it is possible for a humanto receive a great amount more information than it is possible for thehuman mind or bodily organs to process.

This can also be understood from the difference in sizes between thepart of the human brain which governs the receiving of information andthe part of the human brain which governs the generation of information.The auditory/visual part of the brain is extremely large. In contrast tothis, the part related to the generation of language is not so large.Nerves a strung throughout all parts of the body, and a variety ofinformation is collected in the brain and the spinal cord. In contrastto the very large amount of information, the information that the braingenerates is limited to the voice and a few gestures. In terms also ofthe thickness of the nerves that are used as information transmissionpaths within the body, the thickest of these is the optic nerve, whichgoverns the reception of information.

This fact can be understood from engineering applications as well.Specifically, in the case of generating image information that a humanbeing will receive, to make image information that the human being willsense as being natural, several megabits per second of information aregenerally required. In images made will less than this amount ofinformation, a human will easily be able to detect unnaturalness ofshape and movement. And a human is not capable of generating this amountof image information. The amount of information in a human facialexpression is extremely small compared with the amount of imageinformation the human eye generally perceives. The analog of this is thevery high compression ratio when an image is bandwidth compressed tocapture a human facial expression. Bandwidth compression of an imageincluding a human facial expression has be researched in detail by Prof.Harashima et al, of University of Tokyo, from which this extremely highcompression ratio is known. That is, the amount of information in thehuman facial expression is extremely small. Virtually the same is trueof the voice. Using current bandwidth compression technology, voiceinformation can be compressed to approximately 4 kilobits per second.That is, the amount of information is small.

In the case in which music from an musical instrument, rather than avoice, is to be used to generate information, the amount of informationis small. Consider the amount of information from a piano performance. Apiano has 88 keys and, therefore, when one is pressed data less than 7bits is generated. If it is possible for a fast person to press ten keysin one second, there are ten fingers, and additionally, if there are1000 sound levels (10 bits) which the sound can take, this is7*10*10*10=7000, which is no more than 7 kilobits per second. This doesnot change with the model and the tone of the piano. When recording apiano performance, the required information speed is generally no morethan 1000 bits per second. While it appears that a large amount ofinformation is generated by a musical instrument when it is played, theamount of information generated by the musical instrument only appearsto be large because the information of the tone and individuality of themusical instrument is modulated by information that is generated by ahuman being.

On the other hand, in the case of receiving information, a human beingis capable of receiving and processing a very large amount ofinformation. With an orchestra of 150 people generating information, ifeven one performer makes a mistake, it can be easily detected.Additionally, a human being is constantly distinguishing sound from theextremely large amount of information generated by the performers'modulation of the characteristic information generated by theinstruments, and perceiving and extracting characteristics therefrom.

Consider the case of five people having a serious discussion. Eachperson is receiving information from the other four people, who aremaking all efforts to express their opinions to the other person. Whileall of the information from the other four people is not processed inthe receiving person's brain, it is at least received via the person'ssensory organs. Even after the meeting, the participants have a generalgrasp of who said what. This is possible because, of the informationreceived from the other four persons, the required parts were processedby the brain. With regard to information generation, it is generally notpossible for one person to generate an amount of information thatexceeds the total of the average information generated by the other fourpersons.

That is, there is a large difference in the amount of information that ahuman being can generate and receive. Specifically, the amount ofinformation that a human being generates is extremely small compared tothe amount of information that can be received by a human.

The amount of information transmitted in a personal-use electronicapparatus of the past was small compared to the amount of informationthat a single human being can generate. That is, it was no more than asmuch as a voice transmission. Therefore, this human being clearlygenerated less information that the human being was intrinsicallycapable of generating. However, when wider bandwidth radio communicationbecomes possible in the future, it will be possible to perform radiotransmission at a transmission rate that is lower than the informationreceiving rate of a human being and greater than the informationgenerating rate of a human being. When this is done, it will not bepossible as in the past to make effective use of frequencies with thesame rate for both transmitting and receiving.

In the past, the same modulation method was used in the uplink and thedownlink. For example, in a narrowband digital automobile telephonesystem using the TDMA of Japan and the US, π/4DWPSK was used on both thedownlink and the uplink. A proposal to use different modulation methodson the uplink and downlink was made in the US digital automobiletelephone standards (IS-95) which uses OQPSK. In this, the uplink usesOQPSK (Offset Quadrature Phase Shift Keying-4) and the downlink usesQPSK (Quadrature Phase Shift Keying-4). However, the informationtransmission rates are the same, this clearly differing from the SDLsystem. Also, because the same PSK modulation is used, thecharacteristics are extremely similar. There are no examples of usingmodulation methods of completely different natures and with completelydifferent transmission rates.

The thirteenth embodiment of the present invention is shown in FIG. 15.Communication is performed by a radio communication terminal 101, whichis connected to a cable network, and a portable radio terminal 102. Therelationship between the frequency band used for this communication andthe transmission rate is shown in FIG. 16.

Transmission from the radio communication terminal 101 to the portableterminal 102 is performed via a radio circuit (downlink) at atransmission rate of R1 at a radio frequency of f1 in the 60-GHz band.In this embodiment, because BSPK, which is a two-state modulationmethod, is used, the transmission rate and the used bandwidth are notedas the same. R1 is the 100-Mbps transmission rate, it is possible toachieve a 100-MHz bandwidth by using the 60-GHz band, and it is possibleto implement wideband transmission.

Transmission from the portable terminal 102 to the radio communicationterminal 101 is performed via a radio circuit (uplink) at a transmissionrate R1, which is lower than R1, at a frequency of f2 in the 800-MHzband. Because the information that is generated at the portable terminal102 can be thought of as being mainly input from keys and voice,sufficient information transmission can be performed with a transmissionrate of several tens of kilobits per second. In this embodiment, thiswas made 30 kbps. If this is 30 kbps, because sufficient bandwidth canbe achieved even in the 800-MHz band, transmission is possible at thisbandwidth.

Because the radio frequency band at the terminal is low, there is littlepropagation loss in the air, so that the power need not be made thatlarge. Also, because the transmitted bandwidth is small, the total poweris also small. For this reason, it is possible to reduce the powerconsumption, enabling a lengthening of the period of continuous usebefore recharging or replacement of the battery.

In addition, devices for the 800-MHz band are widely used in automobiletelephones, and inexpensive devices are readily available. Reduction ofthe size of devices is also being achieved. By placing the uplink in the800-MHz band, it is possible to reduce the cost and the size of theterminal.

The fourteenth embodiment of the present invention is shown in FIG. 17.

Communication is performed between a radio communication terminal 301,which is connected to a cable network and a portable radio terminal 202.In doing this, the relationship of the radio frequency placement and thetransmission rate is as shown in FIG. 18.

Transmission from the radio communications terminal 301 to the portableterminal 302 is performed via a radio circuit (downlink) at atransmission rate of R1 at a radio frequency of f1 in the 60-GHz band.R1 is a high-speed circuit of, for example, 100 Mbps. Along with this,another single downlink is provided for transmission at a rate of R2(for example, 30 kbps) at f2′ in the 800-MHz band. Transmission from theportable terminal 302 to the radio communication terminal 301 isperformed via a radio circuit (uplink) at a transmission rate of R2 at aradio frequency of f2 in the 800-MHz band.

The difference in this in comparison with the thirteenth embodiment isthe provision of on more downlink, at f2 and R2. The 60-GHz-banddownlink, because of the characteristics of that frequency band, issusceptible to the influence of obstructing objects. Because ofshadowing caused by obstructing objects, cutoff of the communicationcircuit occurs. In this embodiment, by providing a link by theadditional one downlink at f2′, it is possible to prevent the totalcutoff of the downlink. Compared to the radio frequency f1 in the 60-GHzband, the radio frequency f2′ in the 800-MHz band has less propagationloss and is less susceptible to shadowing, thereby reducing thepossibility of circuit cutoff. For example, by assigning a controlchannel to this f2′/R2 downlink, even in the event that the f1/R1downlink is cut off, there is no complete cutoff, the link between theradio terminal 301 and the portable terminal 302 being maintained byexecuting such protocols as the completion protocol, the upper stateprotocol, and the cutoff protocol via the control channel. In this case,although the portable radio terminal 302 an additional f2′/R2 receivingapparatus, compared to the 60-GHz-band receiving apparatus, the addedpart has neglible small current consumption, volume, and cost. Byadopting the radio frequency bands and transmission rate configurationof this embodiment, it is possible to implement a high-performanceportable terminal which is small, has low power consumption, and whichis low cost.

The fifteenth embodiment of the present invention is shown in FIG. 19.

Communication is performed between a radio base station 501, which isconnected to a cable network, and a plurality of portable radioterminals 502. The relationship between the radio frequency band and thetransmission rates in this embodiment is shown in FIG. 20. From theradio base station 501 to each of the portable terminals 502 (downlink)transmission is made on frequencies f1, f1′, f1″ in the 60-GHz band at atransmission rate of R1. From each of the portable terminals 502 to theradio base station 501 (uplink) transmission is made on frequencies f2,f2′, and f2″ in the 2.4-GHz band at a transmission rate of R2, R1 is 100MHz, and R2 is 2 MHz. In doing this, one base station and a plurality ofterminals perform wideband transmission over a millimeter downlink andrelatively narrowband transmission over a 2.4-GHz-band uplink. Thefrequency placement at each of the terminals, as shown in FIG. 8, isconfigured such that f2 follows and corresponds to f1 and such that f2′follows and corresponds to f1′. In this embodiment, while frequencymultiplexing is used on both the uplink and the downlink, it is alsopossible to employ multiplexing by time-division multiplexing,coding-division multiplexing, or the ALOHA system or the like. In thisembodiment, because the uplink transmission rate is a relatively high 2MHz, the 2.4-GHz band is used. Compared with the 800-MHz band, the2.4-GHz band has higher propagation loss, but compared with the 60-GHzband it has much lower propagation loss, so that, compared to the casein which the same 60-GHz band is used for the uplink and the downlink,it is possible to limit the terminal power to a low power. It ispossible to make the influence of the terminal on a human being small,and to have a configuration which has low power consumption, small size,and low cost.

The sixteenth embodiment of the present invention is shown in FIG. 21.

Communication is performed between a radio base station 701, which isconnected to a cable network, and a plurality of portable terminals 702.The relationship of the radio frequency placement and the transmissionrate in this embodiment is shown in FIG. 22. The downlink performscommunication at a transmission rate of R1 at a frequency of f1 in the19-GHz band. In this case, R1 is 50 Mbps. Another downlink is provided,this performing communication at a transmission rate of R2 (for example,2 kbps) at a frequency of f3 in the 400-MHz band. The uplink performscommunication at a transmission rate of R2 at a frequency of f2 in the400-MHz band. The frequency placement, as shown in FIG. 10, isconfigured such that the frequency sequence is f1, f2, f3 for theterminal 1 and f1′, f2′, f3′ for the terminal 2. If this type offrequency placement is used, it is possible to have uniformly spacedradio frequencies in the narrowband 400-MHz-band uplink and downlink,making it easy to establish synchronization of the terminal frequency.By placing the f1 in the 19-GHz band, a wideband downlink isestablished, and by placing the downlink and uplink in the 400-MHz band,the possibility of complete cutoff is reduced, thereby enabling stablecontrol. Because the receiver for the downlink in the 400-MHz band canhave a simple configuration, it can be implemented without muchinfluence on the overall size of the terminal. By configuring the uplinkwith a low transmission rate on the low 400-MHz band, it is possible toprovide a simple portable terminal.

The seventeenth embodiment of the present invention is shown in FIG. 23.This relates to the radio section (radio apparatus) of a portable radioterminal applied to the radio communication system of the thirteenth andfifteenth embodiments of the present invention. The radio apparatus ofthe seventeenth embodiment is formed by an antenna 901 and receiver forthe purpose of receiving a f1/R1 radio signal, an antenna 903 andtransmitter for the purpose of transmitting a f2/R2 radio signal, aninterface 906 between the receiver, the portable terminal and otherparts, and a control apparatus 906. In this case, f1 is in ahigh-frequency band (for example, in the 60-GHz band), R1 is wideband(for example, 100 Mbps), f2 is in a low-frequency band (for example,800-MHz band), and R2 is narrowband (for example, 30 kbps). Because thefrequency bands and bandwidths differ between receiving andtransmitting, independent antennas are used for receiving andtransmitting. The receiver includes a frequency converting apparatus anddemodulating apparatus for the purpose of converting the RF-bandfrequency radio signal to a digital signal. The transmitter includes adigital modulator and frequency converting apparatus to convert adigital signal to an RF (radio frequency). The control apparatus hasfunctions which establish the timing of the transmitting and receivingwith synchronized frequency and transmission rate.

By providing a portable terminal with a radio apparatus of this type ofconfiguration, it is possible to configure a portable terminal which canbe applied to the radio communication system of the thirteenth andfifteenth embodiments.

The eighteenth embodiment of the present invention is shown in FIG. 24.This embodiment is related to a radio section (radio apparatus) of aportable radio terminal which is applied to a radio communication systemof the twelfth and fourteenth embodiments. The difference in this withrespect to the fifteenth embodiment is a receiving apparatus 1004 whichreceives a narrowband (for example, 30 kbps) signal at a frequency of f2in a low-frequency band (for example, in the 800-MHz band), and atransmitting/receiving sharer (duplexer) which includes both the f2transmitting signal and the received signal in a single antenna. A800-MHz-band transmitting apparatus 1005 and the receiving apparatus1004 are inexpensive in comparison to a 60-GHz-band receiving apparatus,and facilitate a reduction in size. Also, because transmission is doneat a low frequency and narrow bandwidth, the transmitting power can bemade small. This enables the implementation of a portable radio terminalwhich has little influence on the human body.

By providing a portable terminal with a radio apparatus of this type ofconfiguration, it is possible to configure a portable terminal which canbe applied to the radio communication system of the twelfth andfourteenth embodiments.

The nineteenth embodiment of the present invention is shown in FIG. 25.This embodiment relates to a radio apparatus and radio base stationwhich are applied to a radio communication system of the thirteenth andfifteenth embodiment. This embodiment will be described using theexample of a radio base station. The base station has a transmittingapparatus 1101, which performs transmission at a transmission rate of R1(for example, 100 Mbps) at a radio frequency of f1 in a millimeter band(for example, 60-GHz band), and a receiving apparatus which performsreceiving of at a transmission rate of R2 which is lower than R2 (forexample, 30 kbps) at a radio frequency of f2 in a low frequency band(for example, 800-MHz band). In addition, there is control section, anda signal processing section and interface section which performconnections to a cable network.

By providing a receiving apparatus and a transmitting apparatus whichhave different frequency bands and transmission rates, it is possible toconfigure a radio apparatus and a radio base station which can beapplied to the radio communication system of the second embodiment andthe fourth embodiment.

The twenty-first embodiment of the present invention is shown in FIG.27. The twenty-first embodiment is a radio communication system made upof a base station 1301 and a terminal 1302. The base station is formedby a transmitter 1303 which performs transmission by infrared rays at atransmission rate of R1, a receiver 1304 which performs receiving of ata transmission rate of R2 on a radio frequency of f2, and a signalprocessing section which performs control and performs interfacing witha cable network. The terminal is formed by an infrared receiver 1305, aradio transmitter 1306, and a signal processing section which performsinterface with other parts and control. Transmission from the basestation to a terminal (downlink) is performed using infrared at atransmission rate of R1. Transmission from a terminal to the basestation (uplink) is performed using radio at a transmission rate of R1.

In the case in which the downlink is implemented as a radio circuitusing radio waves, it is necessary to have a bandwidth which correspondsto the transmission rate. In the case in which high-speed transmissionis performed, it is necessary to achieve a wide bandwidth, and it isnecessary to develop a high frequency band that is yet unused, such as amillimeter band. However, in this embodiment, by using infrared waves onthe downlink which requires a wide bandwidth, it is possible toconfiguration the system without a limitation imposed by radio frequencybandwidths. Additionally, millimeter-band devices are high in cost andphysically large, whereas infrared devices are low-cost and physicallysmall, enabling the implementation of a terminal and base station thatare small and low-cost.

The twenty-second embodiment of the present invention is shown in FIG.28. The base station radio apparatus 1401 is formed by a transmittingapparatus which performs transmission at a high transmission rate of R1(100 Mbps) at a frequency f1 in a first radio frequency band (forexample, 60 GHz) and a receiving apparatus which performs receiving of asignal at a transmission rate R2 (for example, 30 kbps) which is lowerthan R1 at a frequency f2 in a radio frequency band that is lower thanf1 (for example 800 MHz). The radio apparatus of the terminal is formedby a receiving apparatus which performs receiving of a f1/R1 signal anda transmitting apparatus which performs transmission of an f2/R2 signal.

In this system, the f1/R1 signal and the f2/R2 signal have differentmodulation methods.

The frequency f1 is in a millimeter band, and R1 is approximately 100Mbps. It is difficult to obtain a device which operates linearly oversuch a wide bandwidth in a millimeter band. Therefore, on the downlinkit is desirable to use a non-linear modulation method. The radiopropagation characteristics in a millimeter band are such that there isa large propagation loss, and because the distance being traveled by theradio waves is short, frequency usage can be effectively improved bymeans of zone design. Because millimeter waves provide a relative amountof spectrum bandwidth margin, the utilization efficiency on thefrequency axis is not as severe as with previous microwaves. For thisreason, a method of modulation is allowed which has a relatively widebandwidth in comparison with the transmission rate. Because of both ofthese aspects FSK, which is a non-linear modulation system, having amodulation index of 0.5 or greater, thereby requiring some bandwidth, isa candidate.

On the other hand, because the frequency of the uplink is microwave(f2), and the transmission rate (R2) is several tens of kbps, it is easyto obtain low-cost, compact linear components, thereby eliminatingproblems of linearity. However, because the bandwidths allocated in thisfrequency band are small, it is necessary to make efficient use of thefrequency axis. For this reason, a method of modulation having superiorfrequency utilization efficiency is desired. Although they are linearmodulation, the π/4DQPSK and QPSK modulation methods, which havesuperior frequency utilization efficiency, and GMSK, which has aslightly inferior efficiency are candidates.

From another viewpoint, on the high-speed downlink, because of the speedof the transmission rate, QAM, which enables the transmission of muchinformation with a single symbol, is a candidate. On the uplink, thetransmission rate is slow, but because the associated information isimportant control information and the like, BPSK and the like, which aremore immune to errors than QAM (Quadrature Amplitude Modulation-4) arecandidates.

As described above, in an SDL system, because the uplink and downlinktransmission rates and transmission frequency bands differ, by selectingdifferent modulation systems for each, it is possible to obtain ahigh-quality circuit on each.

The twenty-third embodiment of the present invention is shown in FIG.29. The base station and terminal shown in this embodiment are thoseshown in FIG. 28. Transmission on the downlink from the base station1501 to each terminal 1502 is done at a transmission rate of R1 (100Mbps) at a frequency f1 in the 60-GHz band, using a modulation method 1(code division multiplexing, CDM), and transmission on the uplink fromeach terminal in the base station is done at a transmission rate of R2(8 kbps) at a frequency of f2 in the 800-MHz band, using a modulationmethod 2 (GMSK). By changing the transmission rates, transmittingfrequency bands, and modulation methods of the uplink and downlink, itis possible to achieve a high-quality circuit on both, while enablingreduction in size and power consumption of the terminal.

The twenty-fourth embodiment of the present invention is shown in FIG.30. The base station 1601 has a transmitting apparatus 1603 fortransmission at a transmission rate of R1 at a radio frequency of f1 ina sub-millimeter band (19 GHz). The transmission rate R1 is not fixed,but can be varied in the transmission rate range of 1 Mbps to 15 Mbps.The modulation method 1 is 4-value FSK. At the terminal, in the samemanner, a receiving apparatus 1606 is provided for receiving at atransmission rate of R1, using a modulation method 1, at a frequency off1. On this wideband downlink, mainly transmission of data such asimages, which requires a wide bandwidth, is performed. The base stationand terminal have, separate from this downlink, a π/4DQPSK transceiverfor a transmission rate of R2 (384 kbps) on a frequency of f2 (1.9 GHz).Because transmission on the frequency of f2 is don by time-divisionmultiple access/time-division multiplexing (TDMA/TDD), transmission isdone on the same frequency. FIG. 31 is a conceptual drawing of thesystem configuration which uses the base station and terminal of FIG.30. The base station 1701 has a f1/R1, modulation method 1 downlink, anda modulation method 1, f2/R2 uplink and downlink. By using this type ofconfiguration, it possible to obtain a high-quality circuit on each, andfurther possible to configure a system that has few instantaneousdropouts caused by shadowing.

In this twenty-fourth embodiment, the f2 uplink and downlink use thesame transmission rate of R2. Having an uplink with a transmission rateof R2 and a downlink with a transmission rate of R2′ can also beenvisioned. While the f2 uplink and downlink are mainly used fortransmission of control information, in addition to simple controlinformation the uplink also performs data transmission of re-transmittedcontrol, in the case in which an error occurs in f1 downlink data, anduplink data transmission. Because downlink data transmission isperformed on a high-speed downlink at f1, the f2 downlink only performstransmission of control data. Therefore, even on the f2 uplink anddownlink, there occurs an symmetry in the amount of information. Radiocommunication systems of the past did not consider asymmetry ofinformation, assigning the same bandwidth to the uplink and thedownlink. On the f2 circuit, which mainly transmits control information,by considering an uplink and a downlink with differing transmissionrates, it is possible to achieve a more efficient utilization offrequencies.

The twenty-fifth embodiment of the present invention will be describedbelow, with reference made to the drawings.

First, the digital radio communication system related to thetwenty-fifth embodiment of the present invention will be explained inaccordance with FIG. 32.

There is a base station and a plurality of portable electronicapparatuses, an downlink circuit transmission of information from thebase station to a portable electronic apparatus, and an uplink circuitfor transmission information from a portable electronic apparatus to abase station. The downlink circuit and the uplink circuit can be, forexample, an SDL-Net as shown in the first through the twelfthembodiments. With an SDL-Net, the area covered by a high-speed downlinkcircuit is made narrow, and the area covered by a low-speed uplinkcircuit is made wide. In addition, the signal transmission rate of theuplink circuit is made slower than the signal transmission rate of thedownlink circuit, to give consideration to the reduction in size of theportable electronic apparatus.

FIG. 33 shows an example of the configuration of a portable electronicapparatus used in an SDL-Net. A digital signal transmitted from aportable electronic apparatus to a base station undergoeserror-correcting encoding, and is waveshaped and modulated in a digitalsection, is converted to an analog signal by means of a D-A converter(DAC) and an interpolating filter (LPF), and is input to a mixer. At themixer, the signal which is output from the DAC is multiplied by a signalwhich is output from a carrier signal generator (oscillation frequencyf1), the output of the mixer undergoing suppression of images after themultiplication by means of a bandpass filer (BPF), and amplification bymeans of an RF amplifier, after which it is output by means of anantenna. The downlink signal transmitted from the base station isreceived by an antenna and bandlimited by means of a bandpass filter(BPF), after which it is amplified by an LNA (low-noise amplifier). Theoutput of the LNA is input to a mixer, by which it is multiplied by asignal which is output from a carrier signal generator (oscillatorfrequency f2), thereby converting the frequency. The output of the mixerundergoes suppression of images after multiplication, by means of theLPF, after which an A-D converter (ADC) converts it to a digital signal.The ADC output (digital signal) is demodulated at the digital section.

In an SDL-Net, the uplink signal transmission rate and the downlinksignal transmission rate differ (the downlink signal transmission ratehaving a high speed than that of the uplink). That is, the timing clocksfor the uplink and the downlink differ. According to the presentinvention, a clock which is supplied to a digital section of the uplinkis merely connected from the clock for the downlink via a 1/n frequencydivider, enabling simplification of the circuit cf.

The frequency divider is, as shown in FIG. 34, made up of a base-ncounter and a phase shifter. By means of this, the signal transmissionrate of the uplink and the downlink differ, and in a system in which theuplink signal transmission rate is . . . than the downlink signaltransmission rate, it is possible to use a common system clockgenerator, thereby enabling simplification of the circuit configuration.Also, by adopting the circuit configuration shown in FIG. 34, it ispossible to generate the clock for the uplink circuit with an arbitraryphase. This operation will be described by means of FIG. 35. Thedownlink circuit clock is frequency divided by a base-n counter, andphase shifted by an arbitrary timing by the phase shifter. By adoptingthe above-noted configuration it is possible to synchronize the signalstransmitted on the uplink an the downlink.

Next, a digital radio communication method related to the twenty-sixthembodiment will be described, using FIG. 36.

In the radio communication method related to the twenty-sixth embodimentthere is a PHS circuit and a high-speed downlink circuit, the methodbeing made up of a information service base station which is connectedto a cable network, a PHS base station which is connected to theabove-noted information service base station, and a high-speed downlinkcircuit base station. Signal transmission from the information servicebase station to a portable electronic apparatus is performed by eitherthe PHS circuit or a high-speed downlink. Signal transmission from theportable electronic apparatus to the information service base station isperformed by means of the PHS circuit.

FIG. 37 shows the configuration of the radio section and the modemsection of the portable electronic apparatus which is used in the radiocommunication system of FIG. 36. Because of one type of uplink circuitand two types of downlink circuits, each of the transmitting sectionsand receiving sections are housed together. A received radio signal isdemodulated by the radio section and modem section, and sent to thecontrol section and memory section. A digital signal output from thecontrol section and the memory section is sent to the radio section andthe modem section and transmitted as a radio signal.

When a radio signal is demodulated, the carrier and timing clock must beregenerated from the received signal. FIG. 38 shows the configuration ofthe receiver when performing regeneration the carrier and the timingclock. The radio signal received by the antenna is amplified by the RFamplifier (the RF amplifier output being hereinafter referred to as theRF signal). At the carrier regeneration circuit, the reference carrieris regenerated from the RF signal. The regenerated reference carrier isinput to a multiplier. Simultaneously with this, the RF signal is inputto a mixer, by which its frequency is converted. The multiplier outputis input to a lowpass filter (LPF) for the purpose of eliminating imagesignals caused by the frequency conversion (the output of the LPF beinghereinafter referred to as the baseband signal). At the timingregeneration circuit, the timing clock is regenerated from the basebandsignal. Therefore, in a portable electronic apparatus used in the radiocommunication system shown in FIG. 36, because radio signals arereceived at two different signal transmission rates, two timingregeneration circuits such as shown in FIG. 38 are required (FIG. 39).That is, it is necessary to have a timing regeneration circuit 1 toregenerate the timing clock from the baseband signal 1, and a timingregeneration circuit 2 to regenerate the timing clock from the basebandsignal 2.

According to the present invention, it is possible to replace the slowerspeed of the two timing regeneration circuits with the divider and phaseshifter shown in FIG. 34, thereby simplifying the circuit cf. Inaddition, it is possible to synchronize the transmission timing of thehigh-speed downlink circuit and the PHS circuit.

In the twenty-sixth embodiment, although PHS was given as the examplegiven of a radio communication system in which the signal transmissionrates were equal, this can also be a different kind of radiocommunication system, such as an automobile telephone.

Next, a digital radio communication method related to the twenty-seventhembodiment will be described.

With the configuration of the portable electronic apparatus shown inFIG. 39, it is necessary to have two types of carrier regenerationcircuits and clock regeneration circuits. This is shown in a simplemanner in FIG. 40. The RF signal 1 and the RF signal 2, the basebandsignal 1, and the baseband signal 2 are each used to performregeneration of carriers and timing. As shown in FIG. 33, according tothe present invention, it is possible to replace the other clockgenerating circuit by a frequency divider and a phase shifter, therebyenabling simplification of the circuit cf. In addition, the presentinvention can be applied no only to the clock regeneration circuit, butto the carrier regeneration circuit as well. FIG. 41 shows an example ofthe present invention applied to a carrier regeneration circuit.

The reference signal generating circuit shown in FIG. 41 generates andoutputs carriers and timing clocks with respect to the RF signal 1 andRF signal 2, and the baseband signal 1 and the baseband signal 2 whichare input to it.

At the carrier regeneration circuit or the timing clock regenerationcircuit, by extracting the carrier component or the clock component fromthe input signal by means of a highly selective (high Q) circuit, suchas a PLL, it is possible to regenerate the carrier or the timing clock.That is, by eliminating from the input signal the error component, usinga filter, regeneration is made of either the carrier or the timingclock.

While in the carrier regeneration circuit or clock regeneration circuitshown in FIG. 41, regeneration of the carrier or of the timing clock isperformed from a signal of each, with the reference signal regeneratingcircuit shown in FIG. 42, because it is possible to perform regenerationof the carrier or timing clock from a plurality of input signals, it ispossible to obtain a plurality of error information. For this reason,the regenerated carrier or timing clock frequency accuracy can beimproved.

Next, a digital radio communication method related to the twenty-eightembodiment will be described. In the radio communication method shown inFIG. 32 or FIG. 36, when transmitting information from the base stationto a portable electronic apparatus or from a portable electronicapparatus to a base station, transmission is done in units of frames, aframe being made up of a plurality of continuous bits. By treating thetransmitted signal in units of frames, it is possible to easily applyerror correction or ARQ. FIG. 43 shows a block diagram of a frame timingdetecting circuit which performs frame timing clock regeneration from ademodulated bit data stream. Let us assume a receiver configuration asshown in FIG. 44. A digital bit stream which was demodulated by theabove-noted digital section is input to a correlator along with the abit timing clock. The correlator is formed from cascaded D-typeflip-flops (a shift register) and a comparator. The comparator has inputto it the output of the shift register, which is delayed by the bittiming clock, and a known signal which is inserted beforehand for thepurpose of frame detection. The correlator output is input to a PLL, andthe frame timing clock is generated. In a radio communication method inwhich there are two or more communication systems having differingsignal transmission rates and frame timings, two or more frame timingdetecting circuits as shown in FIG. 42 are required.

According Lo the present invention as described above, it is possible toreplace a signal source with a frequency divider and phase shifter.Therefore, it is possible to have a single PLL replace two or more typesof frame synchronization circuits, thereby enabling simplification ofthe circuit cf. It is possible to implement a frame timing detectingcircuit with a frequency divider and a phase shifter. FIG. 43 shows anexample of a frame timing detecting circuit implemented with a frequencydivider and a phase shifter.

The demodulated bit stream 1 and the bit timing clock 1 are input to acorrelator 1, and the trigger signal of the frame timing is detected.The output of the correlator 1 is input to a phase-locked loop which isformed by a phase comparator, a loop filter, a voltage-controlledoscillator, and a base-m counter. One output of the voltage-controlledoscillator is input to the frequency divider shown in FIG. 34. Theamount phase shift of the phase shifter is controlled by the output ofthe correlator 2.

In addition, because the frame timing can be generated by frequencydividing the bit timing clock, it is possible to have a common circuitserve as the bit timing clock regeneration circuit and the frame timingregeneration circuit. FIG. 44 shows a clock signal generating circuit.The error signal is detected from a plurality of inputs such as a clocksignal (number of inputs i) and the voltage-controlled oscillator iscontrolled, it being possible to derive the desired clock (output signalk) by means of base-nk counter and a phase shifter. By using theabove-noted configuration, it is possible to simplify the circuit cf.

Next, a radio communication system related to the twenty-ninthembodiment will be described in accordance with FIG. 45. FIG. 45 showsthe configuration, which is made up of a PHS base station and cablenetwork, and an SDL-Net. The SDL-Net has a downlink which has a highspeed compared to the PHS, this being mainly used for data transmission.In the PHS circuit, position recording is performed.

As described above, in a system in which two or more different types oftransmission system exist, it is possible to simplify the circuitconfiguration by replacing one of the clock regeneration circuits by afrequency divider and phase shifter. However, in doing this, it isnecessary to have the clocks of the differing transmission methodssynchronized. FIG. 45 shows a method of synchronizing, via the network,a PHS circuit and an SDL-Net circuit. The network side has a referencesignal generator. At the PHS base station a signal which is synchronizedto a reference signal on the network side is generated by asynchronizing circuit. When performing communication between with aportable electronic apparatus, the signal is transmitted based on thisreference signal. At the SDL-Net base station, in the same manner, asignal which is synchronized to a reference signal on the network sideis generated by a synchronizing circuit, information being transmittedto a portable electronic apparatus based on this reference signal. Thesynchronizing circuit is formed by a clock generating circuit such as aPLL and, as described above, this can be implemented by a frequencydivider and a phase shifter.

Next, a radio communication system related to the thirtieth embodimentof the invention will be described. As in the case of theabove-described FIG. 45, in a system made up of a PHS base station, acable network, and an SDL-Net base station, the case in which theservice areas of the PHS and the SDL-Net is assumed. That is, as shownin FIG. 46, the SDL-Net services areas are included within the PHSservice area. The existence of a plurality of SDL-Net service area isenvisioned.

In the above-described SDL system, there are systems existing which havea narrowband uplink radio channel and a wideband downlink radio channel,and systems which have a narrowband radio channel for both uplink anddownlink. Because the system for which the present invention is intendedis the latter type of system, hereinafter the term SDL system shall beused to refer to this latter type of system. In an SDL system, toachieve a high transmission rate on the downlink radio channel, a highfrequency is used at the wideband radio base station, but becauseattenuator at high frequencies is high, it is difficult to achieve awide service area. Also, because the wider the bandwidth is made, themore the transmission distortion increases and the greater is theinfluence of noise, a wideband radio base station service area isnarrower than a narrowband radio base station service area. For thisreason, the areas of a wideband radio base station service and anarrowband radio base station service area have different makeups.Therefore, in an SDL system, accompanying the movement of a mobile radiostation, with the same connectable narrowband base station, there arecases in which the connectable wideband base station will change, sothat a mobile radio station must be aware of both the connectablenarrowband base station and the connectable wideband base station. Withregard to the method of recognizing in the service area of whatnarrowband base station a mobile radio station is located, because bothup and down radio channels are provided between a narrowband basestation and the mobile radio station, it is possible to use the sameprotocol as has been used in previous portable telephone services. Theprotocol that is used in a portable telephone service consists ofnotification by the radio base station, via the downlink channel, ofitself by means of an identifying signal, this signal being received bythe mobile station, which sends to that base station an identifyingsignal which indicates its identity, via the uplink channel. By doingthis, the mobile radio station can determine in the service area of whatradio base station it is located. With regard to the method ofrecognizing in the service area of what wideband base station a mobileradio station is located, the above description did not provide anexplicit method. Therefore, in a system for which the present inventionis intended, there was no method with regard to recognizing in theservice area of what wideband base station a mobile radio station islocated. As a result of there being no method in existence forrecognizing in the service area of what wideband base station a mobileradio station is located, this being essential to starting the provisionof communication service, in a system which included as a constituentelement a mobile radio station not having a wideband uplink radiochannel, it was not possible to start communication. In addition, evenwhen in the condition of providing service, it was not possible tomaintain service when the mobile radio station moves into the servicearea of a different radio base station, that is, handover was notpossible.

In a radio communication system related to the thirty-first through thethirty-ninth embodiment, as shown in the conceptual drawing of FIG. 47the above-noted mobile radio station 51 has an optimum connectionstation interpreting means 61 which receives a signal for the purpose ofidentifying the above-noted wideband radio base station 52, notificationof which is made from the above-noted wideband radio base station 52 viaa radio circuit, and which interprets from this signal the widebandradio base station that is suitable for connection, an optimum basestation notification means 62, which gives notification to theabove-noted server 56 of an above-noted specific wideband radio basestation 52 that is suitable for connection to an above-noted mobileradio station, via the above-noted narrowband radio base station 53, anda service starting means 63, which starts the above-noted prescribedservice via the above-noted specific wideband radio base station 52which is judged to be suitable for connection with respect to theabove-noted mobile radio station.

In the case in which handover must be performed, in addition to theabove-noted means, a radio communication system related to thethirty-first through the thirty-ninth embodiment of the presentinvention has a means which, when the above-noted mobile radio stationreceives the above-noted service via an above-noted specific widebandradio base station, receives a signal for the purpose of identifying theabove-noted wideband radio base station, notification of which is givenvia a radio circuit from a wideband radio base station which isdifferent from the above-noted specific wideband radio station, andwhich interprets from this received signal to which wideband radio basestation should switching be made, a means by which the above-notedmobile radio station notifies the above-noted server via the above-notednarrowband radio base station of a wideband radio base station which issuitable as a switching destination, and a means by which theabove-noted server switches a connection with respect to the above-notedmobile radio station, that connection is made via the above-notedspecified wideband radio base station, which is judged to be suitable asa switching destination for connection, thereby providing theabove-noted prescribed service.

By virtue of adopting the above-noted constitution, a mobile radiostation that receives a signal for the purpose of identifying a widebandradio base station, notification of which is given from a wideband radiobase station, can, by interpreting the received signal, determine awideband radio base station which is suitable for connection. The mobileradio station uses the uplink radio channel from the mobile radiocircuit to the narrowband radio base station to tell the narrowbandradio base station to what wideband radio base station it is connected.Because the narrowband radio base station and server are connected viathe network, it is possible the narrowband radio base station can notifythe server, via the network, as to what wideband radio base station themobile radio station is connected. By doing this, even if there is nouplink radio channel from the mobile radio station to the wideband radiobase station, it is possible for the mobile radio station to have theserver recognize to what wideband radio base station connection issuitable, and the server is able to start the provision of service tothe mobile radio station via the wideband radio base station that isjudged suitable for connection.

In the condition of providing the prescribed service via one of thewideband radio base stations, with regard to maintaining the service inthe case in which the mobile radio station moves to the service area ofa different wideband radio base station, according to the presentinvention, a signal for the purpose of identifying a wideband radio basestation, notification of which is given via a radio circuit from awideband radio base station, and interpreting that received signal, ajudgment is made as to what wideband radio base station suitable forconnection switching should be made. The mobile radio station notifiesthe server via the narrowband radio base station of to what widebandradio base station suitable for connection switching should be made. Bydoing this, because it is possible to cause the server to recognize towhat wideband radio base station suitable for connection switchingshould be made, it is possible for the server to continuing providingservice by switching via the wideband radio base station which wasjudged to be suitable for connection.

First, a radio communication system for which the thirty-first throughthe thirty-ninth embodiments were intended will be described. FIG. 48 isa conceptual drawing which shows the configuration of a system relatedto the present invention. In FIG. 48, the numeral 51 denotes a mobileradio station, 52 and 53 are radio base stations, 56 is a server, and 57is a network. The radio base station 52 (this hereinafter being referredto as the wideband radio base station 52) has a transmitting means forthe purpose of wideband information transmission. With respect to this,the radio base station 53 (hereinafter referred to as the narrowbandradio base station 53) has a transmitting/receiving means for thepurpose of narrowband information transmission. The mobile radio station51 s a terminal which performs information transmission with thewideband radio base station 52 or the narrowband radio base station 53.The radio channel between the wideband radio base station 52 and themobile radio station 51 is called the wideband radio channel, and theradio channel between the narrowband radio base station 53 and themobile radio station 51 is called the narrowband radio channel.

While in FIG. 48, as a convenience, a distinction is made between thewideband radio base station 52 and the narrowband radio base station 53,as shown in FIG. 49, it is also acceptable for a single radio basestation 58 to have both a transceiving means for the purpose ofnarrowband information transmission and a transmission means for thepurpose of wideband information transmission. In this case, although thecost of the relay base station 58 becomes high, the total number ofradio base stations in the system is reduced. If there is a need toperform control between the transceiving means for the purpose ofnarrowband information transmission and the transmitting means for thepurpose of wideband information transmission, this control is made easy.What follows is a description, using FIG. 48, of the thirty-firstthrough thirty-ninth embodiments of the present invention which, inwhich the wideband relay base station 52 and the narrowband relay basestation 53 are separate radio base stations.

The thirty-first embodiment: The procedure for starting communicationwill be described for the thirty-first embodiment for the case in whichthe mobile radio station 51 is in the area shown in FIG. 50A, that is,the case in which the mobile radio station 51 can connect to thewideband radio base station 52. FIG. 51 is the most basic flowchartrelated to the thirty-first embodiment. At step ST1, the mobile radiostation 51 interprets in what wideband relay base station 52's servicearea it is located. At step ST2, the information interpreted at step ST1is passed to the server 56 via the narrowband relay base station 53. Bydoing this, the server 56 can recognize in which wideband relay basestation 52's service area the mobile radio station 51 is located. Atstep ST3, service is started to be provided with respect to the mobileradio station 51, via the wideband relay base station 52 which wasinterpreted at step ST1. In actuality, when service is started to beprovided, a variety of procedures can be envisioned, based on theabove-described basic flowchart. FIG. 52 is one example. At step ST11,the mobile radio station 51 interprets in what wideband relay basestation 52's service area it is located. At step ST12, a judgment ismade as to whether a user has made a service request. In the case inwhich there is a service request from a user, flow proceeds to stepST13, but if there is no request, step ST11 is repeated. At step ST13,selection is made as to whether the wideband downlink radio channel isto be used to receive service. If the wideband downlink radio channel isto be used to receive service, flow proceeds to step ST14, but if not,flow proceeds to step ST16. At step ST14, the information interpreted atstep ST11 is passed to the server 56 via the narrowband relay basestation 53. At step ST15, the provision of service to the mobile radiostation 51 is started, via the wideband relay base station interpretedat step ST11. If, however, at step ST13 the selection was not to use thewideband downlink radio channel to receive service, that is, if theselection was made to use the narrowband downlink radio channel toreceive service, at step ST16 the fact that the mobile radio station 51will use the narrowband downlink radio channel to receive service isreported to the server 56. At step ST17, service is begun to be providedto the mobile radio station 51 via the narrowband radio base station 53.

In the above-noted thirty-first embodiment, although the example shownis that in which at step ST13 the service is to be received via thewideband radio channel, this being executed at step ST14, if step ST14is after step ST11, it is acceptable to execute this, regardless of theexistence or non-existence of a service request. That is, even if thereis no service request from a user, the information interpreted at stepST11 may be passed to the server 56 via the narrowband radio basestation 53. In this case, regardless of whether there is a servicerequest from a user, the server 56 is able to tell which wideband radiobase station 52 service area the mobile radio station 51 is located.There is a sequence in which only if step ST12 is executed before stepST11, that is, only in the case in which there is a service request froma user. In this case, if there is no request from a user, because themobile radio station 51 does not need to interpret in which widebandrelay base station 52 service area it is located, there is a reductionof power consumption. For a further reduction in power consumption, itis possible to switch off the power to the receiving means for receivingwideband information.

Next the sequence diagram for the communication starting procedurerelated to the first invention will be described, using FIG. 53. Themobile radio station 51 receives from the wideband radio base station 52a signal 511 for the purpose of identifying the radio base station, andfrom this signal is able to judge which relay base station 52 servicearea it is located in. In this condition, if a service request occurs,the user performs a dialup 511 of the specific telephone number of theserver 56, and a communication circuit is secured from the mobile radiostation 51 to the server 56, via the narrowband relay base station 53.After securing the communication circuit from the mobile radio station51 to the server 56, the mobile radio station 51 sends to the server 56a data transmission request message 512 and a signal 513 for the purposeof identifying a wideband relay base station 52 to which it can beconnected. The server 56 interprets the data request message 512 and thesignal 513 sent from the user, and sends information 514 which the userhas requested, via the wideband relay base station 52 which is specifiedby the signal 513.

The thirty-second embodiment: The procedure for starting communicationwill be described for the thirty-first embodiment for the case in whichthe mobile radio station 51 is in the area shown in FIG. 50B, that is,the case in which the mobile radio station 51 cannot connect to thewideband relay base station 52. FIG. 54 is the most basic flowchartrelated to the thirty-second embodiment. At step ST21, the mobile radiostation 51 interprets that it is not located in a wideband radio basestation 52 service area. At step ST22, the information that the basestation 51 will use the narrowband downlink radio channel is passed tothe server 56 via the narrowband relay base station 53. The provision ofservice to the mobile radio station 51 is started, via the narrowbandrelay base station 53. When the service is started, a variety ofprocedures can be envisioned, based on the above-described basicflowchart.

FIG. 55 is one example. At step ST31, the mobile radio station 51interprets that it is not in a wideband radio base station 52 servicearea, that is, that it cannot connect to the wideband radio base station52. At step ST32, a judgment is made as to whether there is a servicerequest which used the narrowband downlink radio channel. In the case inwhich there is a service request from a user, flow proceeds to stepST33, and if there is no service request, step ST31 is repeated. At stepST33, the mobile radio station 51 passes the fact that it will use thenarrowband radio base station 53 to the server 56, via the narrowbandradio base station 53. At step ST34, the provision of service to themobile radio station 51 is started, via the narrowband radio basestation 53. Although in the above-described embodiment, after aninterpretation is made that the mobile radio station 51 cannot connectto the wideband radio base station 52, that is, after a determination ismade as to whether or not connection to the wideband radio base station52 can be made, the example shown is that of making a judgment at stepST32 of whether there is a service request from a user, it is possible,as shown in the thirty-first embodiment, to execute the step ST31 afterdetermining whether there is a request from a user.

Next the sequence diagram for the communication starting procedurerelated to the second invention will be described, using FIG. 56. Themobile radio station 51 cannot receive from the wideband radio basestation 52 a signal 541 for the purpose of identifying the radio basestation. Even if it could receive it, the signal strength is not greatenough for the purpose of receiving the service. Therefore, the mobileradio station 51 interprets this as meaning that it is outside theservice area of the wideband radio base station. That is, the mobileradio station 51 recognizes that it can only receive the service via thenarrowband downlink radio channel. In such a case as this, the userselects whether or not to receive the service via the narrowbanddownlink radio channel. If the service is to be received via thenarrowband downlink radio channel, the user performs a dialup 540 of thespecific telephone number of the server 56, and a communication circuitis secured via the narrowband radio base station. After securing thecommunication circuit from the mobile radio station 51 to the server 56,the mobile radio station 51 sends a data transmission request message542 and a signal 543, for the purpose of identifying the a narrowbandradio base station 53 to which connection can be made, to the server.Usually, because the narrowband radio base station 53 used as thedownlink radio channel is the same narrowband radio base station 53 usedas the uplink radio channel, the signal 543 may merely be only theinformation to inform the server 56 that the wideband downlink radiochannel cannot be used. The server 56 interprets the data transmissionrequest message 542 and the signal 543 sent from the user, and sends theinformation 544 requested by the user either via the narrowband radiobase station 53 which is specified by the signal 543, or via the uplinkradio channel.

Next, the procedure with regard to handover in each of the thirty-thirdto thirty-sixth embodiments will be described.

The handover which is handled by these embodiments is limited to ahandover that occurs in the case in which the mobile radio station 51moves within the service area of a specific narrowband radio basestation 53. The reason for this is that, because the narrowband radiobase station 53 has uplink and downlink radio channels, handover betweennarrowband radio base stations can be adequately performed using theprocedure of the past. Because the procedure when starting communicationwas shown for the thirty-first and thirty-second embodiments, thehandover procedure will be described from the condition of alreadyproviding service in the thirty-third to thirty-six embodiments.

Thirty-third embodiment: The handover procedure will be described forthe case in which the mobile radio station 51 moves as shown in FIG.50C, that is, in the case in which the mobile radio station 51 isreceiving service in the service area of the wideband radio base station52, and moves into the service area of a different wideband radio basestation 52.

FIG. 57 is the most basic flowchart related to this embodiment. At stepST41, a judgment is made as to whether or not the mobile radio station51 can receive the a signal sent from a wideband radio base station 52different from the one from which service is being provided. In the casein which receiving is possible, the mobile radio station 51 interpretsthe destination wideband radio base station 52 for handover, based onthe results of a comparison of the received signal field strength withthe received signal field strength of the signal sent from the widebandradio base station 52 which is currently providing service. Therefore,in the case in which the field strength of the signal being sent by thewideband radio base station 52 which is currently providing service issufficient, service continues and switching of the radio station is notperformed. The criterion for selecting whether or not switching of theconnection is to be done varies depending upon the communication qualityrequired by the service being provided. For example, in the case ofvoice communication service, because the required communication qualityis not that high, even if movement of the mobile radio station 51 isaccompanied by a slight deterioration in communication quality, However,in the case of data communication service, because the requiredcommunication quality is higher than in the case of voice communicationservice, switching of the radio base station is done to assure the bestpossible communication quality. At step ST42, the informationinterpreted at step ST41 is passed to the server 56 via the narrowbandradio base station 53. By doing this, the server 56 is able to recognizethe destination wideband radio base station 52 for handover. At stepST43, switching of the connection is performed so that service isprovided via the wideband radio base station which was judged to be thedestination of the handover.

Next, the handover sequence diagram will be described, using FIG. 58. Inthe case in which the mobile radio station 51 moves as shown in FIG.50C, because the signal strength when receiving the information data 565transmitted from the wideband radio base station 52 deteriorates, itbecomes impossible to receive it properly. Because the mobile radiostation moves into the service area of a different wideband radio basestation, it can now receive the signal 566 for the purpose ofidentifying a radio base station notified from the other wideband radiobase station, and it is possible for it to make a judgment, from thatreceived signal, of what wideband radio base station 52 service area ithas moved into. The mobile radio station 51 makes a judgment of whetheror not handover should be done, based on the relationship of thereceived field strengths of the information signal 565 and the signal566. If there is no need to perform handover, receiving of theinformation data 565 continues as is.

In the case in which the need to perform handover arises, the mobileradio station 51 sends a handover request message and a signal 558, forthe purpose of identifying the handover destination wideband radio basestation 52, to the server 56. When the server 56 interprets the handoverrequest message and the signal 568, it sends a circuit cutoff requestmessage 569 to the wideband radio base station which is currentperforming communication. After the circuit is cut off, the server sendsthe information data 570 via the wideband radio base station 52 whichwas specified by the signal 568. By doing this, even in the case inwhich the service area changes because of movement of the user, it ispossible for the user to continue receiving the service.

Thirty-fourth embodiment: The handover procedure for the thirty-fourthembodiment will be described for the case in which the mobile radiostation 51 moves as shown in FIG. 50D, that is, for the case in whichthe mobile radio station 51 is receiving service in the service area ofa wideband radio base station 52, and moves outside the service area ofthe wideband radio base station 52. Because the mobile radio station 51moves outside the service area, the received signal strength of thesignal sent from the wideband radio base station 52 which is currentlyproviding service deteriorates. Also, it is not possible for it toreceive a signal sent from a wideband radio base station 52 differentfrom the wideband radio base station 52 providing service. Therefore, atstep ST51, the mobile radio station 51 interprets that it cannot connectto the wideband radio base station 52. At step ST52, the mobile radiostation 51 informs the server 56 via the narrowband radio base station53 that it cannot connect to the wideband radio base station 52, thatis, that it will use the narrowband radio base station 53 for downlinkchannel transmission. At step ST53, the server 56 switches theconnection so that service in continued via the narrowband radio basestation 53.

In the above-described embodiment, the example provided was that of thecase in which the assumption was made that the mobile radio station 51could no longer connect to a wideband radio base station 52 andswitching is made to connect via a narrowband radio base station, it ispossible to add a step after step ST51 which selects either continuedprovision of service using the narrowband downlink radio channel orstoppage of the provision of service. In the case in which the selectionof continued service is made, the flow proceeds to step ST52. The casein which the service is to be stopped is described in detail with regardto the thirty-fifth embodiment.

Next, the sequence diagram for handover with relation to thethirty-fourth embodiment will be described, using FIG. 60. In the casein which the mobile radio station 51 moves as shown in FIG. 50D, becausethere is a deterioration in the received field strength of theinformation data signal 585 which is sent from the wideband radio basestation, it is no longer possible to properly receive the information.Because the mobile radio station 51 moves outside the service area ofthe wideband radio base station 52, it is not possible for it to receivethe signal 586 which is for the purpose of identifying a radio basestation sent from different wideband radio base station 52. Even itcould receive it, it is not possible to obtain a signal strengthsufficient for the provision of service. Therefore, the mobile radiostation 51 interprets that it is located outside the wideband radio basestation 52 service area. That is, it recognizes that it cannot receiveservice via a narrowband downlink radio channel. For this reason,switching is made to connect to a narrowband downlink radio channel tocontinue the provision of service. The mobile radio station 51 sends tothe server 56 a handover request message 587 and a signal 588 for thepurpose of identifying the handover destination narrowband radio basestation 53.

Normally, because the narrowband radio base station 53 which is used asthe downlink radio channel is the same as the narrowband radio basestation 53 used as the uplink radio channel, the signal 588 may merelybe only the information to inform the server 56 that the widebanddownlink radio channel cannot be used. When the server 56 interprets thehandover request message, 587 and the signal 588, it sends a circuitcutoff request message 589 to the wideband radio base station 52 whichis currently performing communication. After the circuit is cut off, theserver 56 sends the information 590 requested by the user, either viathe narrowband radio base station 53 which was specified by the signal588, or via the narrowband radio base station 53 used on the uplinkradio channel. By doing this, even in the case in which the service areachanges because of movement of the user, it is possible for the user tocontinue receiving the service.

Thirty-fifth embodiment: The circuit service stopping procedure, thatis, the circuit cutoff procedure will be described, using FIG. 61, forthe case in which the mobile radio station 51 moves as shown in FIG.50E, that is, in the case in which the mobile radio station 52 isreceiving service inside the service area of a wideband radio basestation 52, and moves outside the service area of the wideband radiobase station 52.

Because the mobile radio station 51 moves outside the service area ofthe wideband radio base station 52, there is deterioration of thereceived field strength of the signal sent from the wideband radio basestation 52 currently providing service. It is also impossible to receivethe signal sent from a wideband radio base station other than thewideband radio base station currently providing service. Therefore, atstep ST61, the mobile radio station interprets that it cannot connect toa wideband radio base station. At step ST62, the mobile radio station 51informs the server 56 via the narrowband radio base station, that itcannot connect to a wideband radio base station 52, that is, that theprovision of service is to be stopped. At step ST63, the server 56performs a stoppage of the service being provided, and cuts off thecommunication circuit from the wideband radio base station to the mobileradio station 51. In the case in which, as in the thirty-fourthembodiment, a step is added which selects either continued provision ofservice using the narrowband downlink radio channel or stoppage of theprovision of service, this step follows step ST61, and if stoppage ofthe service is selected at this step, flow proceeds to step ST62.

Next, the sequence diagram for handover in the thirty-fifth embodimentwill be described, using FIG. 62. In the case in which the mobile radiostation 51 moves as shown in FIG. 50E, because the signal strength whenreceiving the information data signal 605 sent from the wideband radiobase station 52 deteriorates, it is no longer possible to receive itproperly. Because the mobile radio station 51 moves outside the servicearea of the wideband radio base station 52, it cannot receive the signal606 from another wideband radio base station which is for the purpose ofidentifying the radio base station. Even it could receive it, it is notpossible to obtain a signal strength sufficient for the provision ofservice. Therefore, the mobile radio station 51 interprets that it islocated outside the wideband radio base station 52 service area. Thatis, it recognizes that it cannot receive service via a wideband downlinkradio channel. For this reason, the stoppage of the provision of serviceis executed. The mobile radio station 51 sends a communication cutoffrequest message 607 to the server 56. When the server interprets thecommunication cutoff request message 607, it sends a circuit cutoffmessage 608 to the mobile radio station 51, via the wideband radio basestation 52 which is currently performing communication. By doing this,it is possible to quickly stop the service being provided, in accordancewith the wish of the user.

Thirty-sixth embodiment: The handover procedure will be explained usingFIG. 63, for the case in which the mobile radio station 51 moves asshown in FIG. 50E, that is, in the case in which the mobile radiostation 51 is outside the service area of a wideband radio base station52 and is receiving service using a narrowband downlink radio channeland then moves into the service area of a wideband radio base station52.

Accompanying the movement of the mobile radio station 51, it becomespossible to receive the signal form the wideband radio base station 52for the purpose of identifying the radio base station. At step ST71, themobile radio station 51 interprets that it has moved to inside a servicearea of a wideband radio base station 52. At step ST72, the informationinterpreted at step ST71 is passed to the server 56, via the narrowbandradio base station 53. By doing this, it is possible for the server torecognize that the mobile radio station 51 has moved to inside a servicearea of a wideband radio base station 52. At step ST73, the connectionis switched so that it passes through the wideband radio base station 52interpreted at step ST71, and the provision of service is continued.Even in the case in which the mobile radio station 51 is using thenarrowband radio channel, it must always be waiting to receive thesignal which is sent by a wideband radio base station 52. The reason forthis is that, when the service area of a wideband radio base station 52is entered, even if signal reception via the narrowband radio basestation is good, there are cases in which handover is performed.

While in the above-noted embodiment, the example described is that inwhich at step ST71, when the mobile radio station 51 interprets that ithas entered a service area of a wideband radio base station 52, ahandover is performed immediately, it is also possible to add a step bywhich the user selects whether or not to perform a handover. The reasonfor this is that, as mentioned above, in the case in which the receivingcondition of the signal via the narrowband radio base station 53 is notnecessarily bad, for a service such as voice communication which doesnot require high-speed transmission, it is not necessary to performhandover. There are three places this step can be added, each having thefollowing characteristics. First, if the above-noted step is addedfollowing step ST72, regardless of whether or not a handover isperformed, the server 56 can recognize in which wideband radio basestation 52 service area the mobile radio station 51 is located. Next, inthe case in which the above-noted step is added following step ST71,when handover is not performed, because the mobile radio station 51 doesnot tell the server in which wideband radio base station 52 service areait is located, there is a reduction in the amount of traffic between themobile radio station 51 and the server 56. Finally, if the above-notedstep is added before step ST71, because it is not necessary for themobile radio station 51 to interpret in which wideband radio basestation 52 service area it is located, there is a reduction in powerconsumption. In this case, if the power supply to the receiving meansfor wideband information transmission is switched off, there is afurther reduction in power consumption.

Next, the handover sequence diagram for the system of the thirty-sixthembodiment will be described, using FIG. 64. In the case in which themobile radio station 51 moves as shown in FIG. 50E, the mobile radiostation 51 becomes capable of receiving the signal 625 from a widebandradio base station 52 for the purpose of identifying the radio basestation, and can make a judgment, based on that received signal, at towhat wideband radio base station 52 service area it has moved into. Atthis time, as described above, the signal strength of the informationdata 624 signal received by the mobile radio station 51 is notnecessarily bad. Therefore, whether or not a handover is performeddepends on the wishes of the user. It is also possible to establishbeforehand whether or not a handover is to be performed when enteringthe service area of a wideband radio base station 52. If the setting ismade so that a handover is not performed, the mobile radio station 51may switch the power supply to the receiver for the purpose of receivingthe wideband information transmission to off. If a handover is not to beperformed when the mobile radio station enters the service area of awideband radio base station 52, reception of the information data signal624 via the narrowband radio base station 52 is continued as is.

In the case of performing a handover, the mobile radio station 51 sendsto the server 56 a handover request message 626 and a signal 627 foridentifying the handover destination wideband radio base station 52.When the server 56 interprets the handover request message 626 and thesignal 627, it sends a downlink radio channel circuit cutoff message 628to the narrowband radio base station 52. After the circuit is cut off,the server 56 sends the information data 629 via the wideband radio basestation 52 which was specified by the signal 627. By doing this, even inthe case in which the service area changes because of movement of theuser, it is possible for the user to continue receiving the service.

Thirty-seventh embodiment: A characteristic logical number is allocatedto the server 56. When a plurality of servers exist in a network, acommon number is allocated to all servers. When a user wishes to receiveservice, the server 56 is called. The methods of calling are the methodof direct dialup by the user of the logical number (FIG. 65A) and themethod of the user selecting an SDL service item which is displayed atthe mobile radio station 51. The SDL service is a service provided usingan SDL system. In the case of this method, a correspondence isestablished between SDL service items and logical numbers, so that whena user selects an SDL service item dialup is automatically performed.With either method, when the call is made to the server 56, the firstthing done is the establishment of a communication circuit from themobile radio station 51 to the narrowband radio base station 53.

Next, the narrowband radio base station 53 makes a connection to theserver 56. In the case in which the network has only one server 56, acommunication circuit is established from the narrowband radio basestation 53 to the server 56. In the case in which the network has aplurality of servers 56, selection is made of the server to which thenarrowband radio base station 53 is to be connected. There are fourmethods of making this selection.

The first method is that in which the narrowband radio base station 53recognizes beforehand which server 56 it is to be connected to, thisserver 56 always being selected. Normally, the connected server is aserver neighboring the narrowband ratio base station 53. The secondmethod is that in which a server 56 having a light load is selected. Inthis method, the narrowband radio base station 53 monitors the load ofthe servers 56 and selects a server 56 having a light load. The thirdmethod is that in which the server 56 is selected which has a lightnetwork load. This method attempts to use a communication path on whichthere is little traffic as the path between the narrowband radio basestation 53 and the server 56. The fourth method is that of combining atleast two of the above three methods. One example of doing this is forthe narrowband radio base station 53 to monitor the server 56 loads, andto select from servers 56 having a load lower than a given load theclosest neighboring server 56 to the narrowband radio base station 53.After the server 56 is selected by means an above-noted method, thecommunication circuit from the narrowband radio base station 53 to theserver 56 is established, this being used to establish a communicationcircuit from the mobile radio station 51 to the server 56.

Thirty-eighth embodiment: As shown in FIG. 66, a specific logical numberis allocated to each service. The user make a call using the logicalnumber of the desired service. The methods of calling are the method ofdirect dialup by the user of the logical number and the method of theuser selecting a service item which is displayed at the mobile radiostation 51. This method will be described as the system related to thethirty-eighth embodiment. In the case of this method, when the userselects the service, automatic dialup is performed with respect to thecorresponding logical number. With either of the methods, when a call ismade to the server 56, the first thing that happens is that acommunication circuit is established from the mobile radio station 51 tothe narrowband radio base station 53.

Next, the narrowband radio base station 53 makes a connection to theserver 56. In the case in which the network has only one server 56, acommunication circuit is established from the narrowband radio basestation 53 to the server 56. In the case in which the network has aplurality of servers 56, selection is made of the server to which thenarrowband radio base station 53 is to be connected. Since the methodsof selection are the same as for the thirty-ninth embodiment, they willnot be included here. When the server 56 selection is performed, thecommunication circuit from the narrowband radio base station 53 to theserver is established, this being used to establish a communicationcircuit from the mobile radio station 51 to the server 56.

Thirty-ninth embodiment: The mobile radio station 51 displays whether itis possible to communicate with a radio base station. Specifically, itdisplays both whether it can connect to a narrowband radio base station53 and whether it can connect to a wideband radio base station 52. Themethod of display includes the method of displaying in step manner thesignal strength each of the base stations (FIG. 67A) and the method ofdisplaying a two-value state of communication possible or not possible(FIG. 67B). For the purpose of the above-noted display, the mobile radiostation 51 has both a means of measuring the received field strengthwhen receiving a signal transmitted from a wideband radio base station52 and displaying the results of this measurement in a form which ahuman can recognize, and a means of measuring the received fieldstrength when receiving a signal transmitted from a narrowband radiobase station 53 and displaying the results of this measurement in a formwhich a human can recognize.

According to the thirty-ninth embodiment, it is possible to recognizewhat kind of service the user is receiving. That is, the user receivesservice via a narrowband downlink radio channel, and the user canrecognize the condition in which it is not possible to receive servicevia a wideband downlink radio channel, the condition in which it ispossible to receive service via a wideband downlink radio channel, andthe like. Therefore, in the case, for example, in which the user islocated in a wideband radio base station 52 service area, it is possiblefor the user to select, based on his or her wishes, whether to notreceive service at this point, but to receive high-speed radiotransmission service which uses a wideband downlink radio channel aftermoving into a wideband radio base station 52 service area, or to receivelow-speed radio transmission service via a narrowband downlink radiochannel at this point. The two steps related to the signal transmittedfrom the wideband radio base station 52 (when the mobile radio station51 receives a first signal from a wideband radio base station 52 via aradio circuit, the step of measuring the receive field strength of thefirst signal, and the step of displaying the received field strength ofthe first signal in a form recognizable by a human being) and the twosteps related to the signal transmitted from the narrowband radio basestation 53 (when the mobile radio station 51 receives a second signalfrom a narrowband radio base station 53 via a radio circuit, the step ofmeasuring the receive field strength of the second signal, and the stepof displaying the received field strength of the second signal in a formrecognizable by a human being) are each individual steps. Therefore, amethod can be envisioned in which, in the case in which the fact thatthe user is not to receive high-speed transmission service via thewideband radio base station 52 is set beforehand, the two steps relatedto the signal transmitted from the wideband radio base station 52 arenot performed. In this case, it is possible to reduce the powerconsumption of the mobile radio station 51.

As described above, according to the thirty-first to the thirty-ninthembodiments of the present invention, even in a system which included asa constituent element a mobile radio station not having a widebanduplink radio, such as in an SDL system, it is possible for the server torecognize to which wideband radio base station connection is possible,and to provide service. Even if, accompanying movement of a mobile radiostation, it becomes necessary to perform a handover, it is possible forthe server to recognize the destination wideband radio base station forthe handover, thereby enabling continued provision of service.

FIG. 68 shows, in the same manner as FIG. 45, a radio communicationsystem of the fortieth embodiment, this being formed by a PHS basestation, a cable network, and an SDL-Net. It differs with respect toFIG. 45 in that fact that there is no PHS receiver provided in theSDL-Net base station, and also in that there is no reference oscillatorin the network. As in FIG. 46, the SDL-Net base station exists withinthe PHS service area. For this reason, by inputting the signal receivedby the PHS receiver to a synchronization circuit, it is possible toestablish synchronization between the PHS and the SDL-Net clock.

FIG. 69 shows the overall configuration of the forty-first embodiment,in which a radio communication system related to the present inventionis applied. A plurality of base stations BS which have prescribedservice areas and a plurality of databases and communication satellitesCS are connected via a network.

1. A radio communication system including at least one base station, anda plurality of terminals, said radio communication system comprising: anuplink which performs radio transmission of data at a first transmissionrate; a low-speed down link which performs radio transmission of thedata at a the first transmission rate; a high-speed downlink whichperforms radio transmission of the data at a second transmission ratewhich is higher than the first transmission rate; a first low-speedtransmitter, provided at said terminal, which transmits a first radiosignal at the first transmission rate to said base station via saiduplink; a first low-speed receiver, provided at the base station, whichreceives the first radio signal, which sent at the first transmissionrate, from said terminal via said uplink; a high-speed transmitter,provided at said base station, which transmits a second radio signal atthe second transmission rate to said terminal via said high-speeddownlink; a high-speed receiver, provided at said terminal, whichreceives the second radio signal at the second transmission rate fromsaid base station via said high-speed downlink; a second low-speedtransmitter, provided at said base station, which transmits a thirdradio signal at the first transmission rate to said terminal via saidlow-speed downlink; and a second low-speed receiver, provided at saidterminal, which receives the third radio signal at the firsttransmission rate from said base station via said low-speed downlink;wherein said uplink and said low-speed downlink establish radiotransmission at a first frequency, and said high-speed down linkestablishes radio transmission at a second frequency which is higherthan said first frequency; and wherein at least said high-speed downlinkand said low-speed uplink form an asymmetric communication path betweensaid base station and said terminal, in which said high-speed uplink isused by said second radio signal at a relatively high transmission rate,and said low-speed uplink is used by said first radio signal at arelatively low transmission rate.
 2. A radio communication systemincluding at least one base station, and a plurality of terminals, saidradio communication system comprising: an uplink which performs radiotransmission of data at a first transmission rate; a low-speed downlinkwhich performs radio transmission of data at the first transmissionrate; a high-speed downlink which performs radio transmission of data ata second transmission rate which is higher than the first transmissionrate; a first low-speed transmitter, provided at said terminal, whichtransmits a first radio signal at the first transmission rate to saidbase station via said uplink; a first low-speed receiver, provided atsaid base station, which receives the first radio signal which istransmitted at the first transmission rate from said terminal via saiduplink; a high-speed transmitter, provided at said base station, whichtransmits a second radio signal at the second transmission rate to saidterminal via said high-speed downlink; a high-speed receiver, providedat said terminal, which receives the second radio signal at the secondtransmission rate from said base station via said high-speed downlink; asecond low-speed transmitter, provided at said base station, whichtransmits a third radio signal at the first transmission rate to saidterminal via said low-speed downlink; and a second low-speed receiver,provided at said terminal, which receives the third radio signal at thefirst transmission rate from said base station via said low-speeddownlink; wherein said uplink and said low-speed downlink establishradio transmission at a first frequency, and said high-speed downlinkestablishes radio transmission at a second frequency which is higherthan said first frequency; and wherein at least said high-speed downlinkand said low-speed uplink form an asymmetric communication path betweensaid base station and said terminal, in which said high-speed uplink isused by said second radio signal at a relatively high transmission rate,and said low-speed uplink is used by said first radio signal at arelatively low transmission rate.
 3. The radio communication systemaccording to claim 2, wherein said uplink and said low-speed downlink,which establish the radio transmission at said first frequency, performradio transmission of the data at the first and third signals,respectively, within a wide communication area; and said high-speeddownlink which establishes the radio transmission at said secondfrequency, performs radio transmission of the data at the second radiosignal in a narrow area.
 4. The radio communication system according toclaim 3, wherein said base station transmits at least user informationto said terminal by said second low-speed transmitter; and said terminaltransmits at least control information to said base station by saidfirst low-speed transmitter.
 5. The radio communication system accordingto claim 3, wherein said base station transmits at least one of controlinformation and voice information to said terminal by said secondlow-speed transmitter.
 6. The radio communication system according toclaim 3, wherein said base station transmits to said terminal anidentifying signal for identifying the base station itself by saidhigh-speed transmitter; and said terminal further comprises saidhigh-speed receiver which receives said identifying signal, base stationnotification means for receiving an optimum base station for aconnection on the basis of said identifying signal received by saidhigh-speed receiver, and said first low-speed transmitter transmittinginformation with respect to said optimum base station which is notifiedby said base station notification means, to said optimum base station.7. The radio communication system according to claim 3, wherein saidbase station transmits to said terminal an identifying signal foridentifying the base station itself by said high-speed transmitter; andsaid terminal further comprises said high-speed receiver which receivessaid identifying signal, base station notification means for notifyingan optimum base station for a connection on the basis of saididentifying signal received by said high-speed receiver and for furthernotifying any other optimum base station when the other optimum basestation is determined to be an optimum base station rather than the basestation during the connection, and said first low-speed transmittertransmitting information with respect to said optimum base station whichis notified by said base station notification means, to said optimumbase station.
 8. The radio communication base station provided in aradio communication system and performing a radio communication with aterminal, comprising: a first low-speed receiver which performs a firstradio communication with a first low-speed transmitter provided at theterminal by using a first radio frequency signal at a first radiotransmission rate; a high-speed transmitter which performs a secondradio communication with a high-speed receiver provided at the terminal,by using a second radio frequency signal different from the first radiofrequency signal at a second transmission rate higher than the firstradio frequency signal; and a second low-speed transmitter whichperforms the first radio communication with a second low-speed receiverprovided at the terminal at the first radio transmission rate; whereinat least said high-speed downlink and said low-speed uplink form anasymmetric communication path between said base station and saidterminal, in which said high-speed uplink is used by said second radiofrequency signal at a relatively high transmission rate, and saidlow-speed uplink is used by said first radio frequency signal at arelatively low transmission rate.
 9. The radio communication basestation according to claim 8, wherein said base station transmits atleast user information to said terminal by said second low-speedtransmitter; and said terminal transmits at least control information tosaid base station by said first low-speed transmitter.
 10. The radiocommunication base station according to claim 8, wherein said basestation transmits at last one of control information and voiceinformation to said terminal by said second low-speed transmitter. 11.The radio communication base station according to claim 8, wherein saidbase station transmits to said terminal an identifying signal foridentifying the base station itself by said high-speed transmitter; andsaid terminal further comprises said high-speed receiver which receivessaid identifying signal, base station notification means for notifyingan optimum base station for a connection on the basis of saididentifying signal received by said high-speed receiver, and said firstlow-speed transmitter transmitting information with respect to saidoptimum base station which is notified by said base station notificationmeans, to said optimum base station.
 12. The radio communication basestation according to claim 8, wherein said base station transmits tosaid terminal an identifying signal for identifying the base stationitself by said high-speed transmitter; and said terminal furthercomprises said high-speed receiver which receives said identifyingsignal, base station notification means for notifying an optimum basestation for a connection on the basis of said identifying signalreceived by said high-speed receiver and for further notifying any otheroptimum base station when the other optimum base station is determinedto be an optimum base station rather than the base station during theconnection, and said first low-speed transmitter transmittinginformation with respect to said optimum base station which is notifiedby said base station notification means, to said optimum base station.13. A radio communication terminal provided in a radio communicationsystem and performing a radio communication with a radio communicationbase station, comprising: a first low-speed transmitter which performs afirst radio communication with a first low-speed receiver provided atthe base station, by using a first radio frequency signal at a firstradio transmission rate; a high-speed receiver which performs a secondradio communication with a high-speed transmitter provided at the basestation, by using a second radio frequency signal different from thefirst radio frequency signal at a second transmission rate higher thanthe first radio frequency signal; and a second low-speed receiver whichperforms the first radio communication with a second low-speedtransmitter provided at the base station at the first radio transmissionrate; wherein at least said high-speed downlink and said low-speeduplink form an asymmetric communication path between said base stationand said terminal, in which said high-speed uplink is used by saidsecond radio frequency signal at a relatively high transmission rate,and said low-speed uplink is used by said first radio frequency signalat a relatively low transmission rate.
 14. The radio communicationterminal according to claim 13, wherein said base station transmits atleast user information to said terminal by said second low-speedtransmitter; and said terminal transmits at least control information tosaid base station by said first low-speed transmitter.
 15. The radiocommunication terminal according to claim 13, wherein said base stationtransmits at least one of control information and voice information tosaid terminal by said second low-speed transmitter.
 16. The radiocommunication terminal according to claim 13, wherein said base stationtransmits to said terminal an identifying signal for identifying thebase station itself by said high-speed transmitter; and said terminalfurther comprises said high-speed receiver which receives saididentifying signal, base station notification means for notifying anoptimum base station for a connection on the basis of said identifyingsignal received by said high-speed receiver, and said first low-speedtransmitter transmitting information with respect to said optimum basestation which is notified by said base station notification means, tosaid optimum base station.
 17. The radio communication terminalaccording to claim 13, wherein said base station transmits to saidterminal an identifying signal for identifying the base station itselfby said high-speed transmitter; and said terminal further comprises saidhigh-speed receiver which receives said identifying signal, base stationnotification means for notifying an optimum base station for aconnection on the basis of said identifying signal received by saidhigh-speed receiver and for further notifying any other optimum basestation when the other optimum base station is determined to be anoptimum base station rather than the base station during the connection,and said first low-speed transmitter transmitting information withrespect to said optimum base station which is notified by said basestation notification means, to said optimum base station.